Commit Graph

192 Commits

Author SHA1 Message Date
наб
6fa118b857 zdb: main: fix unused, remove argsused
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Ahelenia Ziemiańska <nabijaczleweli@nabijaczleweli.xyz>
Closes #12835
2021-12-21 12:05:12 -08:00
Rich Ercolani
c5ccbbdcf6
Allow printing special vdev metaslab groups
Sometimes, we'd like to know info about the metaslab groups
on special vdevs too. So let's make -MM do something useful.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Allan Jude <allan@klarasystems.com>
Signed-off-by: Rich Ercolani <rincebrain@gmail.com>
Closes #12750
2021-11-30 10:26:45 -08:00
Fedor Uporov
2a9c572059
zdb: Report bad label checksum
In case if all label checksums will be invalid on any vdev, the pool
will become unimportable. From other side zdb with -l option will not
provide any useful information why it happened. Add notifications
about corrupted label checksums.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: John Kennedy <john.kennedy@delphix.com>
Signed-off-by: Fedor Uporov <fuporov.vstack@gmail.com>
Closes #2509
Closes #12685
2021-11-10 12:22:00 -07:00
Fedor Uporov
e39fe05b69
Skip spacemaps reading in case of pool readonly import
The only zdb utility require to read metaslab-related data during
read-only pool import because of spacemaps validation. Add global
variable which will allow zdb read spacemaps in case of readonly
import mode.

Reviewed-by: Serapheim Dimitropoulos <serapheim@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Fedor Uporov <fuporov.vstack@gmail.com>
Closes #9095
Closes #12687
2021-11-09 12:50:39 -08:00
Damian Szuberski
6d680e61ef
Update checkstyle workflow env to ubuntu-20.04
- `checkstyle` workflow uses ubuntu-20.04 environment
- improved `mancheck.sh` readability

Reviewed-by: Matthew Ahrens <mahrens@delphix.com>
Reviewed-by: John Kennedy <john.kennedy@delphix.com>
Signed-off-by: szubersk <szuberskidamian@gmail.com>
Closes #12713
2021-11-02 14:02:57 -06:00
Teodor Spæren
01b572bc62
zdb: fix overflow of time estimation
The calculation of estimated time remaining in zdb -cc could overflow,
as reported in #10666. This patch fixes this, by using uint64_t instead
of ints in the calculations.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Teodor Spæren <teodor@sparen.no>
Closes #10666 
Closes #12610
2021-10-15 15:55:34 -07:00
Brian Behlendorf
6954c22f35
Use fallthrough macro
As of the Linux 5.9 kernel a fallthrough macro has been added which
should be used to anotate all intentional fallthrough paths.  Once
all of the kernel code paths have been updated to use fallthrough
the -Wimplicit-fallthrough option will because the default.  To
avoid warnings in the OpenZFS code base when this happens apply
the fallthrough macro.

Additional reading: https://lwn.net/Articles/794944/

Reviewed-by: Tony Nguyen <tony.nguyen@delphix.com>
Reviewed-by: George Melikov <mail@gmelikov.ru>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #12441
2021-09-14 10:17:54 -06:00
Jorgen Lundman
49d8a99a4d
Upstream: zdb inode mapping
Unfortunately macOS reserves inode ID numbers 0-15, and we can
not used them. In macOS port we simply map them really high IDs.

Normally this is hidden inside the _os implementation, but this is
the one place in the common source files.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Jorgen Lundman <lundman@lundman.net>
Closes #12530
2021-09-08 13:56:04 -07:00
Rich Ercolani
b1a1c64313
Fix cross-endian interoperability of zstd
It turns out that layouts of union bitfields are a pain, and the
current code results in an inconsistent layout between BE and LE
systems, leading to zstd-active datasets on one erroring out on
the other.

Switch everyone over to the LE layout, and add compatibility code
to read both.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Matthew Ahrens <mahrens@delphix.com>
Signed-off-by: Rich Ercolani <rincebrain@gmail.com>
Closes #12008
Closes #12022
2021-08-30 14:13:46 -07:00
наб
2c69ba6444 Normalise /*FALLTHR{OUGH,U}*/
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Ahelenia Ziemiańska <nabijaczleweli@nabijaczleweli.xyz>
Issue #12201
2021-07-26 12:07:39 -07:00
наб
4f1009face zdb: zdb_decompress_block: don't needlessly set buf
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Signed-off-by: Ahelenia Ziemiańska <nabijaczleweli@nabijaczleweli.xyz>
Closes #12187
2021-06-07 20:58:23 -07:00
Serapheim Dimitropoulos
86b5f4c121
Livelist logic should handle dedup blkptrs
Update the logic to handle the dedup-case of consecutive
FREEs in the livelist code. The logic still ensures that
all the FREE entries are matched up with a respective
ALLOC by keeping a refcount for each FREE blkptr that we
encounter and ensuring that this refcount gets to zero
by the time we are done processing the livelist.

zdb -y no longer panics when encountering double frees

Reviewed-by: Matthew Ahrens <mahrens@delphix.com>
Reviewed-by: John Kennedy <john.kennedy@delphix.com>
Reviewed-by: Don Brady <don.brady@delphix.com>
Signed-off-by: Serapheim Dimitropoulos <serapheim@delphix.com>
Closes #11480
Closes #12177
2021-06-07 13:09:07 -06:00
наб
94f942c658
libspl: staticify buf and pagesize, rename aok to libspl_assert_ok
Exporting names this short can easily cause nasty collisions with user code.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: John Kennedy <john.kennedy@delphix.com>
Signed-off-by: Ahelenia Ziemiańska <nabijaczleweli@nabijaczleweli.xyz>
Closes #12050
2021-06-03 11:04:13 -06:00
наб
a0d7e27a13 zdb: remove strtok
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: John Kennedy <john.kennedy@delphix.com>
Signed-off-by: Ahelenia Ziemiańska <nabijaczleweli@nabijaczleweli.xyz>
Closes #12094
2021-05-26 14:51:18 -07:00
Toomas Soome
1a1302f8c4
zdb: dump_history needs space
One space is missing from zdb -h output causing strings to be concatenated. (fixing #11940)

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: John Kennedy <john.kennedy@delphix.com>
Signed-off-by: Toomas Soome <tsoome@me.com>
Closes  #12098
2021-05-25 11:33:18 -06:00
Toomas Soome
17b83525f5
zdb: dump_history can be improved
We only recognize some history records, instead, use
same logic as in print_history_records() in zpool_main.c.

Reviewed-by: Igor Kozhukhov <igor@dilos.org>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Toomas Soome <tsoome@me.com>
Closes #11940
2021-04-29 16:44:07 -07:00
Toomas Soome
09131144b7
zdb: ASSERT issues when DEBUG is not defined
If zdb is not built with DEBUG mode, the ASSERT macros will be
eliminated.

This will leave vim defined, but not used (gcc warning) and
checkpoint spacemap validation loop will do nothing.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Toomas Soome <tsoome@me.com>
Closes #11932
2021-04-27 08:33:37 -07:00
Allan Jude
393e69241e
Add zdb -r <dataset> <object-id | file> <output>
While you can use zdb -R poolname vdev:offset:[<lsize>/]<psize>[:flags] 
to extract individual DVAs from a vdev, it would be handy for be able 
copy an entire file out of the pool.

Given a file or object number, add support to copy the contents to a 
file. Useful for debugging and recovery.

Reviewed-by: Jorgen Lundman <lundman@lundman.net>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Allan Jude <allan@klarasystems.com>
Closes #11027
2021-01-27 21:36:01 -08:00
Matthew Ahrens
aa755b3549
Set aside a metaslab for ZIL blocks
Mixing ZIL and normal allocations has several problems:

1. The ZIL allocations are allocated, written to disk, and then a few
seconds later freed.  This leaves behind holes (free segments) where the
ZIL blocks used to be, which increases fragmentation, which negatively
impacts performance.

2. When under moderate load, ZIL allocations are of 128KB.  If the pool
is fairly fragmented, there may not be many free chunks of that size.
This causes ZFS to load more metaslabs to locate free segments of 128KB
or more.  The loading happens synchronously (from zil_commit()), and can
take around a second even if the metaslab's spacemap is cached in the
ARC.  All concurrent synchronous operations on this filesystem must wait
while the metaslab is loading.  This can cause a significant performance
impact.

3. If the pool is very fragmented, there may be zero free chunks of
128KB or more.  In this case, the ZIL falls back to txg_wait_synced(),
which has an enormous performance impact.

These problems can be eliminated by using a dedicated log device
("slog"), even one with the same performance characteristics as the
normal devices.

This change sets aside one metaslab from each top-level vdev that is
preferentially used for ZIL allocations (vdev_log_mg,
spa_embedded_log_class).  From an allocation perspective, this is
similar to having a dedicated log device, and it eliminates the
above-mentioned performance problems.

Log (ZIL) blocks can be allocated from the following locations.  Each
one is tried in order until the allocation succeeds:
1. dedicated log vdevs, aka "slog" (spa_log_class)
2. embedded slog metaslabs (spa_embedded_log_class)
3. other metaslabs in normal vdevs (spa_normal_class)

The space required for the embedded slog metaslabs is usually between
0.5% and 1.0% of the pool, and comes out of the existing 3.2% of "slop"
space that is not available for user data.

On an all-ssd system with 4TB storage, 87% fragmentation, 60% capacity,
and recordsize=8k, testing shows a ~50% performance increase on random
8k sync writes.  On even more fragmented systems (which hit problem #3
above and call txg_wait_synced()), the performance improvement can be
arbitrarily large (>100x).

Reviewed-by: Serapheim Dimitropoulos <serapheim@delphix.com>
Reviewed-by: George Wilson <gwilson@delphix.com>
Reviewed-by: Don Brady <don.brady@delphix.com>
Reviewed-by: Mark Maybee <mark.maybee@delphix.com>
Signed-off-by: Matthew Ahrens <mahrens@delphix.com>
Closes #11389
2021-01-21 15:12:54 -08:00
Matthew Ahrens
808e681238 Memory leak in zdb:import_checkpointed_state()
Reviewed-by: Igor Kozhukhov <igor@dilos.org>
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Matthew Ahrens <mahrens@delphix.com>
Closes #11396
2020-12-28 10:05:55 -08:00
Matthew Ahrens
b6722b871b nvlist leaked in zpool_find_config()
In `zpool_find_config()`, the `pools` nvlist is leaked.  Part of it (a
sub-nvlist) is returned in `*configp`, but the callers also leak that.

Additionally, in `zdb.c:main()`, the `searchdirs` is leaked.

The leaks were detected by ASAN (`configure --enable-asan`).

This commit resolves the leaks.

Reviewed-by: Igor Kozhukhov <igor@dilos.org>
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Matthew Ahrens <mahrens@delphix.com>
Closes #11396
2020-12-28 10:05:31 -08:00
Alexander Motin
f8020c9363
Make metaslab class rotor and aliquot per-allocator.
Metaslab rotor and aliquot are used to distribute workload between
vdevs while keeping some locality for logically adjacent blocks.  Once
multiple allocators were introduced to separate allocation of different
objects it does not make much sense for different allocators to write
into different metaslabs of the same metaslab group (vdev) same time,
competing for its resources.  This change makes each allocator choose
metaslab group independently, colliding with others only sporadically.

Test including simultaneous write into 4 files with recordsize of 4KB
on a striped pool of 30 disks on a system with 40 logical cores show
reduction of vdev queue lock contention from 54 to 27% due to better
load distribution.  Unfortunately it won't help much ZVOLs yet since
only one dataset/ZVOL is synced at a time, and so for the most part
only one allocator is used, but it may improve later.

While there, to reduce the number of pointer dereferences change
per-allocator storage for metaslab classes and groups from several
separate malloc()'s to variable length arrays at the ends of the
original class and group structures.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Matthew Ahrens <mahrens@delphix.com>
Signed-off-by: Alexander Motin <mav@FreeBSD.org>
Closes #11288
2020-12-15 10:55:44 -08:00
Brian Behlendorf
b2255edcc0
Distributed Spare (dRAID) Feature
This patch adds a new top-level vdev type called dRAID, which stands
for Distributed parity RAID.  This pool configuration allows all dRAID
vdevs to participate when rebuilding to a distributed hot spare device.
This can substantially reduce the total time required to restore full
parity to pool with a failed device.

A dRAID pool can be created using the new top-level `draid` type.
Like `raidz`, the desired redundancy is specified after the type:
`draid[1,2,3]`.  No additional information is required to create the
pool and reasonable default values will be chosen based on the number
of child vdevs in the dRAID vdev.

    zpool create <pool> draid[1,2,3] <vdevs...>

Unlike raidz, additional optional dRAID configuration values can be
provided as part of the draid type as colon separated values. This
allows administrators to fully specify a layout for either performance
or capacity reasons.  The supported options include:

    zpool create <pool> \
        draid[<parity>][:<data>d][:<children>c][:<spares>s] \
        <vdevs...>

    - draid[parity]       - Parity level (default 1)
    - draid[:<data>d]     - Data devices per group (default 8)
    - draid[:<children>c] - Expected number of child vdevs
    - draid[:<spares>s]   - Distributed hot spares (default 0)

Abbreviated example `zpool status` output for a 68 disk dRAID pool
with two distributed spares using special allocation classes.

```
  pool: tank
 state: ONLINE
config:

    NAME                  STATE     READ WRITE CKSUM
    slag7                 ONLINE       0     0     0
      draid2:8d:68c:2s-0  ONLINE       0     0     0
        L0                ONLINE       0     0     0
        L1                ONLINE       0     0     0
        ...
        U25               ONLINE       0     0     0
        U26               ONLINE       0     0     0
        spare-53          ONLINE       0     0     0
          U27             ONLINE       0     0     0
          draid2-0-0      ONLINE       0     0     0
        U28               ONLINE       0     0     0
        U29               ONLINE       0     0     0
        ...
        U42               ONLINE       0     0     0
        U43               ONLINE       0     0     0
    special
      mirror-1            ONLINE       0     0     0
        L5                ONLINE       0     0     0
        U5                ONLINE       0     0     0
      mirror-2            ONLINE       0     0     0
        L6                ONLINE       0     0     0
        U6                ONLINE       0     0     0
    spares
      draid2-0-0          INUSE     currently in use
      draid2-0-1          AVAIL
```

When adding test coverage for the new dRAID vdev type the following
options were added to the ztest command.  These options are leverages
by zloop.sh to test a wide range of dRAID configurations.

    -K draid|raidz|random - kind of RAID to test
    -D <value>            - dRAID data drives per group
    -S <value>            - dRAID distributed hot spares
    -R <value>            - RAID parity (raidz or dRAID)

The zpool_create, zpool_import, redundancy, replacement and fault
test groups have all been updated provide test coverage for the
dRAID feature.

Co-authored-by: Isaac Huang <he.huang@intel.com>
Co-authored-by: Mark Maybee <mmaybee@cray.com>
Co-authored-by: Don Brady <don.brady@delphix.com>
Co-authored-by: Matthew Ahrens <mahrens@delphix.com>
Co-authored-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Mark Maybee <mmaybee@cray.com>
Reviewed-by: Matt Ahrens <matt@delphix.com>
Reviewed-by: Tony Hutter <hutter2@llnl.gov>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #10102
2020-11-13 13:51:51 -08:00
Toomas Soome
4e84f67a96
zdb should not output binary data on terminal
The zdb is interpreting byte array as textual string in dump_zap,
but there are also binary arrays and we should not output binary
data on terminal.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Igor Kozhukhov <igor@dilos.org>
Signed-off-by: Toomas Soome <tsoome@me.com>
External-issue: https://www.illumos.org/issues/12012
External-issue: https://www.illumos.org/issues/11713
Closes #11006
2020-10-05 14:05:28 -07:00
Matthew Ahrens
a57f954226
zdb leak detection fails with in-progress device removal
When a device removal is in progress, there are 2 locations for the data
that's already been moved: the original location, on the device that's
being removed; and the new location, which is pointed to by the indirect
mapping.  When doing leak detection, zdb needs to know about both
locations.  To determine what's already been copied, we load the
spacemaps of the removing vdev, omit the blocks that are yet to be
copied, and then use the vdev's remap op to find the new location.

The problem is with an optimization to the spacemap-loading code in zdb.
When processing the log spacemaps, we ignore entries that are not
relevant because they are past the point that's been copied.  However,
entries which span the point that's been copied (i.e. they are partly
relevant and partly irrelevant) are processed normally.  This can lead
to an illegal spacemap operation, for example if offsets up to 100KB
have been copied, and the spacemap log has the following entries:

	ALLOC 50KB-150KB (partly relevant)
	FREE 50KB-100KB (entirely relevant)
	FREE 100KB-150KB (entirely irrlevant - ignored)
	ALLOC 50KB-150KB (partly relevant)

Because the entirely irrelevant entry was ignored, its space remains in
the spacemap.  When the last entry is processed, we attempt to add it to
the spacemap, but it partially overlaps with the 100-150KB entry that
was left over.

This problem was discovered by ztest/zloop.

One solution would be to also ignore the irrelevant parts of
partially-irrelevant entries (i.e. when processing the ALLOC 50-150, to
only add 50-100 to the spacemap).  However, this commit implements a
simpler solution, which is to remove this optimization entirely.  I.e.
to process the entire spacemap log, without regard for the point that's
been copied.  After reconstructing the entire allocatable range tree,
there's already code to remove the parts that have not yet been copied.

Reviewed-by: Serapheim Dimitropoulos <serapheim@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Matthew Ahrens <mahrens@delphix.com>
External-issue: DLPX-71820
Closes #10920
2020-09-17 10:55:30 -07:00
George Amanakis
085321621e
Add L2ARC arcstats for MFU/MRU buffers and buffer content type
Currently the ARC state (MFU/MRU) of cached L2ARC buffer and their
content type is unknown. Knowing this information may prove beneficial
in adjusting the L2ARC caching policy.

This commit adds L2ARC arcstats that display the aligned size
(in bytes) of L2ARC buffers according to their content type
(data/metadata) and according to their ARC state (MRU/MFU or
prefetch). It also expands the existing evict_l2_eligible arcstat to
differentiate between MFU and MRU buffers.

L2ARC caches buffers from the MRU and MFU lists of ARC. Upon caching a
buffer, its ARC state (MRU/MFU) is stored in the L2 header
(b_arcs_state). The l2_m{f,r}u_asize arcstats reflect the aligned size
(in bytes) of L2ARC buffers according to their ARC state (based on
b_arcs_state). We also account for the case where an L2ARC and ARC
cached MRU or MRU_ghost buffer transitions to MFU. The l2_prefetch_asize
reflects the alinged size (in bytes) of L2ARC buffers that were cached
while they had the prefetch flag set in ARC. This is dynamically updated
as the prefetch flag of L2ARC buffers changes.

When buffers are evicted from ARC, if they are determined to be L2ARC
eligible then their logical size is recorded in
evict_l2_eligible_m{r,f}u arcstats according to their ARC state upon
eviction.

Persistent L2ARC:
When committing an L2ARC buffer to a log block (L2ARC metadata) its
b_arcs_state and prefetch flag is also stored. If the buffer changes
its arcstate or prefetch flag this is reflected in the above arcstats.
However, the L2ARC metadata cannot currently be updated to reflect this
change.
Example: L2ARC caches an MRU buffer. L2ARC metadata and arcstats count
this as an MRU buffer. The buffer transitions to MFU. The arcstats are
updated to reflect this. Upon pool re-import or on/offlining the L2ARC
device the arcstats are cleared and the buffer will now be counted as an
MRU buffer, as the L2ARC metadata were not updated.

Bug fix:
- If l2arc_noprefetch is set, arc_read_done clears the L2CACHE flag of
  an ARC buffer. However, prefetches may be issued in a way that
  arc_read_done() is bypassed. Instead, move the related code in
  l2arc_write_eligible() to account for those cases too.

Also add a test and update manpages for l2arc_mfuonly module parameter,
and update the manpages and code comments for l2arc_noprefetch.
Move persist_l2arc tests to l2arc.

Reviewed-by: Ryan Moeller <freqlabs@FreeBSD.org>
Reviewed-by: Richard Elling <Richard.Elling@RichardElling.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: George Amanakis <gamanakis@gmail.com>
Closes #10743
2020-09-14 10:10:44 -07:00
Michael Niewöhner
10b3c7f5e4 Add zstd support to zfs
This PR adds two new compression types, based on ZStandard:

- zstd: A basic ZStandard compression algorithm Available compression.
  Levels for zstd are zstd-1 through zstd-19, where the compression
  increases with every level, but speed decreases.

- zstd-fast: A faster version of the ZStandard compression algorithm
  zstd-fast is basically a "negative" level of zstd. The compression
  decreases with every level, but speed increases.

  Available compression levels for zstd-fast:
   - zstd-fast-1 through zstd-fast-10
   - zstd-fast-20 through zstd-fast-100 (in increments of 10)
   - zstd-fast-500 and zstd-fast-1000

For more information check the man page.

Implementation details:

Rather than treat each level of zstd as a different algorithm (as was
done historically with gzip), the block pointer `enum zio_compress`
value is simply zstd for all levels, including zstd-fast, since they all
use the same decompression function.

The compress= property (a 64bit unsigned integer) uses the lower 7 bits
to store the compression algorithm (matching the number of bits used in
a block pointer, as the 8th bit was borrowed for embedded block
pointers).  The upper bits are used to store the compression level.

It is necessary to be able to determine what compression level was used
when later reading a block back, so the concept used in LZ4, where the
first 32bits of the on-disk value are the size of the compressed data
(since the allocation is rounded up to the nearest ashift), was
extended, and we store the version of ZSTD and the level as well as the
compressed size. This value is returned when decompressing a block, so
that if the block needs to be recompressed (L2ARC, nop-write, etc), that
the same parameters will be used to result in the matching checksum.

All of the internal ZFS code ( `arc_buf_hdr_t`, `objset_t`,
`zio_prop_t`, etc.) uses the separated _compress and _complevel
variables.  Only the properties ZAP contains the combined/bit-shifted
value. The combined value is split when the compression_changed_cb()
callback is called, and sets both objset members (os_compress and
os_complevel).

The userspace tools all use the combined/bit-shifted value.

Additional notes:

zdb can now also decode the ZSTD compression header (flag -Z) and
inspect the size, version and compression level saved in that header.
For each record, if it is ZSTD compressed, the parameters of the decoded
compression header get printed.

ZSTD is included with all current tests and new tests are added
as-needed.

Per-dataset feature flags now get activated when the property is set.
If a compression algorithm requires a feature flag, zfs activates the
feature when the property is set, rather than waiting for the first
block to be born.  This is currently only used by zstd but can be
extended as needed.

Portions-Sponsored-By: The FreeBSD Foundation
Co-authored-by: Allan Jude <allanjude@freebsd.org>
Co-authored-by: Brian Behlendorf <behlendorf1@llnl.gov>
Co-authored-by: Sebastian Gottschall <s.gottschall@dd-wrt.com>
Co-authored-by: Kjeld Schouten-Lebbing <kjeld@schouten-lebbing.nl>
Co-authored-by: Michael Niewöhner <foss@mniewoehner.de>
Signed-off-by: Allan Jude <allan@klarasystems.com>
Signed-off-by: Allan Jude <allanjude@freebsd.org>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Sebastian Gottschall <s.gottschall@dd-wrt.com>
Signed-off-by: Kjeld Schouten-Lebbing <kjeld@schouten-lebbing.nl>
Signed-off-by: Michael Niewöhner <foss@mniewoehner.de>
Closes #6247
Closes #9024
Closes #10277
Closes #10278
2020-08-20 10:30:06 -07:00
Ryan Moeller
0421f257b2
FreeBSD: Add legacy arc_min and arc_max
These tunables were renamed from vfs.zfs.arc_min and 
vfs.zfs.arc_max to vfs.zfs.arc.min and vfs.zfs.arc.max.
Add legacy compat tunables for the old names.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Ryan Moeller <ryan@iXsystems.com>
Closes #10579
2020-07-19 10:15:34 -07:00
Matthew Ahrens
6774931dfa
Extend zdb to print inconsistencies in livelists and metaslabs
Livelists and spacemaps are data structures that are logs of allocations
and frees.  Livelists entries are block pointers (blkptr_t). Spacemaps
entries are ranges of numbers, most often used as to track
allocated/freed regions of metaslabs/vdevs.

These data structures can become self-inconsistent, for example if a
block or range can be "double allocated" (two allocation records without
an intervening free) or "double freed" (two free records without an
intervening allocation).

ZDB (as well as zfs running in the kernel) can detect these
inconsistencies when loading livelists and metaslab.  However, it
generally halts processing when the error is detected.

When analyzing an on-disk problem, we often want to know the entire set
of inconsistencies, which is not possible with the current behavior.
This commit adds a new flag, `zdb -y`, which analyzes the livelist and
metaslab data structures and displays all of their inconsistencies.
Note that this is different from the leak detection performed by
`zdb -b`, which checks for inconsistencies between the spacemaps and the
tree of block pointers, but assumes the spacemaps are self-consistent.

The specific checks added are:

Verify livelists by iterating through each sublivelists and:
- report leftover FREEs
- report double ALLOCs and double FREEs
- record leftover ALLOCs together with their TXG [see Cross Check]

Verify spacemaps by iterating over each metaslab and:
- iterate over spacemap and then the metaslab's entries in the
  spacemap log, then report any double FREEs and double ALLOCs

Verify that livelists are consistenet with spacemaps.  The space
referenced by livelists (after using the FREE's to cancel out
corresponding ALLOCs) should be allocated, according to the spacemaps.

Reviewed-by: Serapheim Dimitropoulos <serapheim@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Co-authored-by: Sara Hartse <sara.hartse@delphix.com>
Signed-off-by: Matthew Ahrens <mahrens@delphix.com>
External-issue: DLPX-66031
Closes #10515
2020-07-14 17:51:05 -07:00
Robert Novak
bfcbec6f5d
Add block histogram to zdb
The block histogram tracks the changes to psize, lsize and asize
both in the count of the number of blocks (by blocksize) and the
total length of all of the blocks for that blocksize.  It also
keeps a running total of the cumulative size of all of the blocks
up to each size to help determine the size of caching SSDs to be
added to zfs hardware deployments.

The block history counts and lengths are summarized in bins
which are powers of two. Even rows with counts of zero are printed.

This change is accessed by specifying one of two options:

zdb -bbb pool
zdb -Pbbb pool

The first version prints the table in fixed size columns.
The second prints in "parseable" output that can be placed into
a CSV file.

Fixed Column, nicenum output sample:
  block   psize                lsize                asize
   size   Count Length   Cum.  Count Length   Cum.  Count Length   Cum.
    512:  3.50K  1.75M  1.75M  3.43K  1.71M  1.71M  3.41K  1.71M  1.71M
     1K:  3.65K  3.67M  5.43M  3.43K  3.44M  5.15M  3.50K  3.51M  5.22M
     2K:  3.45K  6.92M  12.3M  3.41K  6.83M  12.0M  3.59K  7.26M  12.5M
     4K:  3.44K  13.8M  26.1M  3.43K  13.7M  25.7M  3.49K  14.1M  26.6M
     8K:  3.42K  27.3M  53.5M  3.41K  27.3M  53.0M  3.44K  27.6M  54.2M
    16K:  3.43K  54.9M   108M  3.50K  56.1M   109M  3.42K  54.7M   109M
    32K:  3.44K   110M   219M  3.41K   109M   218M  3.43K   110M   219M
    64K:  3.41K   218M   437M  3.41K   218M   437M  3.44K   221M   439M
   128K:  3.41K   437M   874M  3.70K   474M   911M  3.41K   437M   876M
   256K:  3.41K   874M  1.71G  3.41K   874M  1.74G  3.41K   874M  1.71G
   512K:  3.41K  1.71G  3.41G  3.41K  1.71G  3.45G  3.41K  1.71G  3.42G
     1M:  3.41K  3.41G  6.82G  3.41K  3.41G  6.86G  3.41K  3.41G  6.83G
     2M:      0      0  6.82G      0      0  6.86G      0      0  6.83G
     4M:      0      0  6.82G      0      0  6.86G      0      0  6.83G
     8M:      0      0  6.82G      0      0  6.86G      0      0  6.83G
    16M:      0      0  6.82G      0      0  6.86G      0      0  6.83G

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Robert E. Novak <novak5@llnl.gov>
Closes: #9158 
Closes #10315
2020-06-26 15:09:20 -07:00
George Amanakis
b7654bd794
Trim L2ARC
The l2arc_evict() function is responsible for evicting buffers which
reference the next bytes of the L2ARC device to be overwritten. Teach
this function to additionally TRIM that vdev space before it is
overwritten if the device has been filled with data. This is done by
vdev_trim_simple() which trims by issuing a new type of TRIM,
TRIM_TYPE_SIMPLE.

We also implement a "Trim Ahead" feature. It is a zfs module parameter,
expressed in % of the current write size. This trims ahead of the
current write size. A minimum of 64MB will be trimmed. The default is 0
which disables TRIM on L2ARC as it can put significant stress to
underlying storage devices. To enable TRIM on L2ARC we set
l2arc_trim_ahead > 0.

We also implement TRIM of the whole cache device upon addition to a
pool, pool creation or when the header of the device is invalid upon
importing a pool or onlining a cache device. This is dependent on
l2arc_trim_ahead > 0. TRIM of the whole device is done with
TRIM_TYPE_MANUAL so that its status can be monitored by zpool status -t.
We save the TRIM state for the whole device and the time of completion
on-disk in the header, and restore these upon L2ARC rebuild so that
zpool status -t can correctly report them. Whole device TRIM is done
asynchronously so that the user can export of the pool or remove the
cache device while it is trimming (ie if it is too slow).

We do not TRIM the whole device if persistent L2ARC has been disabled by
l2arc_rebuild_enabled = 0 because we may not want to lose all cached
buffers (eg we may want to import the pool with
l2arc_rebuild_enabled = 0 only once because of memory pressure). If
persistent L2ARC has been disabled by setting the module parameter
l2arc_rebuild_blocks_min_l2size to a value greater than the size of the
cache device then the whole device is trimmed upon creation or import of
a pool if l2arc_trim_ahead > 0.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Adam D. Moss <c@yotes.com>
Signed-off-by: George Amanakis <gamanakis@gmail.com>
Closes #9713
Closes #9789 
Closes #10224
2020-06-09 10:15:08 -07:00
George Amanakis
657fd33bcf
Improvements on persistent L2ARC
Functional changes:

We implement refcounts of log blocks and their aligned size on the
cache device along with two corresponding arcstats. The refcounts are
reflected in the header of the device and provide valuable information
as to whether log blocks are accounted for correctly. These are
dynamically adjusted as log blocks are committed/evicted. zdb also uses
this information in the device header and compares it to the
corresponding values as reported by dump_l2arc_log_blocks() which
emulates l2arc_rebuild(). If the refcounts saved in the device header
report higher values, zdb exits with an error. For this feature to work
correctly there should be no active writes on the device. This is also
employed in the tests of persistent L2ARC. We extend the structure of
the cache device header by adding the two new variables mirroring the
refcounts after the existing variables to preserve backward
compatibility in terms of persistent L2ARC.

1) a new arcstat "l2_log_blk_asize" and refcount "l2ad_lb_asize" which
   reflect the total aligned size of log blocks on the device. This is
   also reflected in the header of the cache device as "dh_lb_asize".
2) a new arcstat "l2arc_log_blk_count" and refcount "l2ad_lb_count"
   which reflect the total number of L2ARC log blocks present on cache
   devices.  It is also reflected in the header of the cache device as
   "dh_lb_count".

In l2arc_rebuild_vdev() if the amount of committed log entries in a log
block is 0 and the device header is valid we update the device header.
This will facilitate trimming of the whole device in this case when
TRIM for L2ARC is implemented.

Improve loop protection in l2arc_rebuild() by using the starting offset
of the payload of each log block instead of the starting offset of the
log block.

If the zio in l2arc_write_buffers() fails, restore the lbps array in the
header of the device to its previous state in l2arc_write_done().

If l2arc_rebuild() ends the rebuild process without restoring any L2ARC
log blocks in ARC and without any other error, this means that the lbps
array in the header is pointing to non-existent or invalid log blocks.
Reset the device header in this case.

In l2arc_rebuild() change the zfs_dbgmsg messages to
spa_history_log_internal() making them user visible with zpool history
command.

Non-functional changes:

Make the first test in persistent L2ARC use `zdb -lll` to increase
coverage in `zdb.c`.

Rename psize with asize when referring to log blocks, since
L2ARC_SET_PSIZE stores the vdev aligned size for log blocks. Also
rename dh_log_blk_entries to dh_log_entries to make it clear that
it is a mirror of l2ad_log_entries. Added comments for both changes.

Fix inaccurate comments for example in l2arc_log_blk_restore().

Add asserts at the end in l2arc_evict() and l2arc_write_buffers().

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: George Amanakis <gamanakis@gmail.com>
Closes #10228
2020-05-07 16:34:03 -07:00
Ryan Moeller
154e48eac9
zdb: Fix ignored zfs_arc_max tuning
Running zdb -l $disk shows a warning that zfs_arc_max is being ignored.
zdb sets zfs_arc_max below zfs_arc_min, which causes the value to be
ignored by arc_tuning_update().

Set zfs_arc_min to the bare minimum in zdb, which is below zfs_arc_max.

Reviewed by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Allan Jude <allanjude@freebsd.org>
Reviewed-by: Matthew Ahrens <mahrens@delphix.com>
Reviewed-by: George Melikov <mail@gmelikov.ru>
Signed-off-by: Ryan Moeller <ryan@iXsystems.com>
Closes #10269
2020-04-30 17:48:58 -07:00
George Amanakis
9249f1272e
Persistent L2ARC minor fixes
Minor fixes on persistent L2ARC improving code readability and fixing 
a typo in zdb.c when byte-swapping a log block. It also improves the 
pesist_l2arc_007_pos.ksh test by giving it more time to retrieve log 
blocks on the cache device.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Adam D. Moss <c@yotes.com>
Signed-off-by: George Amanakis <gamanakis@gmail.com>
Closes #10210
2020-04-17 09:27:40 -07:00
George Amanakis
77f6826b83
Persistent L2ARC
This commit makes the L2ARC persistent across reboots. We implement
a light-weight persistent L2ARC metadata structure that allows L2ARC
contents to be recovered after a reboot. This significantly eases the
impact a reboot has on read performance on systems with large caches.

Reviewed-by: Matthew Ahrens <mahrens@delphix.com>
Reviewed-by: George Wilson <gwilson@delphix.com>
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Co-authored-by: Saso Kiselkov <skiselkov@gmail.com>
Co-authored-by: Jorgen Lundman <lundman@lundman.net>
Co-authored-by: George Amanakis <gamanakis@gmail.com>
Ported-by: Yuxuan Shui <yshuiv7@gmail.com>
Signed-off-by: George Amanakis <gamanakis@gmail.com>
Closes #925 
Closes #1823 
Closes #2672 
Closes #3744 
Closes #9582
2020-04-10 10:33:35 -07:00
Matthew Ahrens
9cdf7b1f6b
Improve zfs destroy performance with zio_t-free zio_free()
When "zfs destroy" is run, it completes quickly, and in the background
we locate the blocks to free and free them.  This background activity
can be observed with `zpool get freeing` and `zpool wait -t free ...`.

This background activity is processed by a single thread (the spa_sync
thread) which calls zio_free() on each of the blocks to free.  With even
modest storage performance, the CPU consumption of zio_free() can be the
performance bottleneck.

Performance of zio_free() can be improved by not actually creating a
zio_t in the common case (non-dedup, non-gang), instead calling
metaslab_free() directly.  This avoids the CPU cost of allocating the
zio_t, and more importantly the cost of adding and later removing this
zio_t from the parent zio's child list.

The result is that performance of background freeing more than doubles,
from 0.6 million blocks per second to 1.3 million blocks per second.

Reviewed-by: Paul Dagnelie <pcd@delphix.com>
Reviewed-by: Serapheim Dimitropoulos <serapheim@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: George Wilson <gwilson@delphix.com>
Signed-off-by: Matthew Ahrens <mahrens@delphix.com>
Closes #10034
2020-02-28 14:49:44 -08:00
Justin Keogh
12f7b90c93
zdb: Always print symlink target
When zdb is printing paths, also print the symlink target if it exists.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Matt Ahrens <matt@delphix.com>
Signed-off-by: Justin Keogh <commits@v6y.net>
Closes #9925
2020-02-12 11:36:05 -08:00
Paul Zuchowski
bc67cba7c0
Fix zdb -R with 'b' flag
zdb -R :b fails due to the indirect block being compressed,
and the 'b' and 'd' flag not working in tandem when specified.
Fix the flag parsing code and create a zfs test for zdb -R
block display.  Also fix the zio flags where the dotted notation
for the vdev portion of DVA (i.e. 0.0:offset:length) fails.

Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Paul Zuchowski <pzuchowski@datto.com>
Closes #9640
Closes #9729
2020-02-10 14:00:05 -08:00
Ned Bass
a3403164d7 zdb: add support for object ranges for zdb -d
Allow a range of object identifiers to dump with -d. This may
be useful when dumping a large dataset and you want to break
it up into multiple phases, or to resume where a previous scan
left off. Object type selection flags are supported to reduce
the performance overhead of verbosely dumping unwanted objects,
and to reduce the amount of post-processing work needed to
filter out unwanted objects from zdb output.

This change extends existing syntax in a backward-compatible
way. That is, the base case of a range is to specify a single
object identifier to dump. Ranges and object identifiers can
be intermixed as command line parameters.

Usage synopsis:

    Object ranges take the form <start>:<end>[:<flags>]
        start    Starting object number
        end      Ending object number, or -1 for no upper bound
        flags    Optional flags to select object types:
         A    All objects (this is the default)
         d    ZFS directories
         f    ZFS files
         m    SPA space maps
         z    ZAPs
         -    Negate effect of next flag

Examples:

 # Dump all file objects
 zdb -dd tank/fish 0👎f

 # Dump all file and directory objects
 zdb -dd tank/fish 0👎fd

 # Dump all types except file and directory objects
 zdb -dd tank/fish 0👎A-f-d

 # Dump object IDs in a specific range
 zdb -dd tank/fish 1000:2000

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Ryan Moeller <ryan@ixsystems.com>
Reviewed-by: Paul Zuchowski <pzuchowski@datto.com>
Signed-off-by: Ned Bass <bass6@llnl.gov>
Closes #9832
2020-01-24 11:00:46 -08:00
Paul Zuchowski
f12e42cccf zdb -d should accept the numeric objset id
As an alternative to the dataset name, zdb now allows the decimal 
or hexadecimal objset ID to be specified.  When permanent errors
are reported as 2 hexadecimal numbers (objset ID : object ID) in 
zpool status; you can now use 'zdb <pool>[/objset ID] object' to
determine the names of the objset and object which have the error.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Ryan Moeller <ryan@ixsystems.com>
Signed-off-by: Paul Zuchowski <pzuchowski@datto.com>
Closes #9733
2020-01-16 09:22:49 -08:00
Ned Bass
8b3438e503 zdb: print block checksums with 6 d's of verbosity
Include checksums in the output of 'zdb -dddddd' along
with other indirect block information already displayed.

Example output follows (with long lines trimmed):

$ zdb -dddddd tank/fish 128
Dataset tank/fish [ZPL], ID 259, cr_txg 10, 16.2M, 93 objects, rootbp DV

    Object  lvl   iblk   dblk  dsize  dnsize  lsize   %full  type
       128    2   128K   128K   634K     512     1M  100.00  ZFS plain f
                                               168   bonus  System attri
    dnode flags: USED_BYTES USERUSED_ACCOUNTED USEROBJUSED_ACCOUNTED
    dnode maxblkid: 7
    path    /c
    uid     0
    gid     0
    atime    Sat Dec 21 10:49:26 2019
    mtime    Sat Dec 21 10:49:26 2019
    ctime    Sat Dec 21 10:49:26 2019
    crtime    Sat Dec 21 10:49:26 2019
    gen    41
    mode    100755
    size    964592
    parent    34
    links    1
    pflags    40800000104
Indirect blocks:
               0 L1  0:2c0000:400 0:c021e00:400 20000L/400P F=8 B=41/41
               0  L0 0:227800:13800 20000L/13800P F=1 B=41/41 cksum=167a
           20000  L0 0:25ec00:17c00 20000L/17c00P F=1 B=41/41 cksum=2312
           40000  L0 0:276800:18400 20000L/18400P F=1 B=41/41 cksum=24e0
           60000  L0 0:2a7800:18800 20000L/18800P F=1 B=41/41 cksum=25be
           80000  L0 0:28ec00:18c00 20000L/18c00P F=1 B=41/41 cksum=2579
           a0000  L0 0:24d000:11c00 20000L/11c00P F=1 B=41/41 cksum=140a
           c0000  L0 0:23b000:12000 20000L/12000P F=1 B=41/41 cksum=164e
           e0000  L0 0:221e00:5a00 20000L/5a00P F=1 B=41/41 cksum=9de790

        segment [0000000000000000, 0000000000100000) size    1M

Reviewed-by: Kjeld Schouten <kjeld@schouten-lebbing.nl>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Ned Bass <bass6@llnl.gov>
Closes #9765
2019-12-30 09:14:40 -08:00
Paul Zuchowski
f0bf435176 zio_decompress_data always ASSERTs successful decompression
This interferes with zdb_read_block trying all the decompression
algorithms when the 'd' flag is specified, as some are
expected to fail.  Also control the output when guessing
algorithms, try the more common compression types first, allow
specifying lsize/psize, and fix an uninitialized variable.

Reviewed-by: Ryan Moeller <ryan@ixsystems.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Paul Zuchowski <pzuchowski@datto.com>
Closes #9612 
Closes #9630
2019-12-10 15:51:58 -08:00
Matthew Macy
2a8ba608d3 Replace ASSERTV macro with compiler annotation
Remove the ASSERTV macro and handle suppressing unused 
compiler warnings for variables only in ASSERTs using the 
__attribute__((unused)) compiler annotation.  The annotation
is understood by both gcc and clang.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Jorgen Lundman <lundman@lundman.net>
Signed-off-by: Matt Macy <mmacy@FreeBSD.org>
Closes #9671
2019-12-05 12:37:00 -08:00
Paul Zuchowski
5a08977374 Fix zdb_read_block using zio after it is destroyed
The checksum display code of zdb_read_block uses a zio
to read in the block and then calls zio_checksum_compute.
Use a new zio in the call to zio_checksum_compute not the zio
from the read which has been destroyed by zio_wait.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Igor Kozhukhov <igor@dilos.org>
Signed-off-by: Paul Zuchowski <pzuchowski@datto.com>
Closes #9644
Closes #9657
2019-12-03 14:37:15 -08:00
Paul Zuchowski
894f6696b4 Add display of checksums to zdb -R
The function zdb_read_block (zdb -R) was always intended to have a :c 
flag which would read the DVA and length supplied by the user, and 
display the checksum. Since we don't know which checksum goes with 
the data, we should calculate and display them all.

For each checksum in the table, read in the data at the supplied 
DVA:length, calculate the checksum, and display it. Update the man 
page and create a zfs test for the new feature.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Kjeld Schouten <kjeld@schouten-lebbing.nl>
Signed-off-by: Paul Zuchowski <pzuchowski@datto.com>
Closes #9607
2019-11-27 10:08:18 -08:00
Matthew Macy
da92d5cbb3 Add zfs_file_* interface, remove vnodes
Provide a common zfs_file_* interface which can be implemented on all 
platforms to perform normal file access from either the kernel module
or the libzpool library.

This allows all non-portable vnode_t usage in the common code to be 
replaced by the new portable zfs_file_t.  The associated vnode and
kobj compatibility functions, types, and macros have been removed
from the SPL.  Moving forward, vnodes should only be used in platform
specific code when provided by the native operating system.

Reviewed-by: Sean Eric Fagan <sef@ixsystems.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Igor Kozhukhov <igor@dilos.org>
Reviewed-by: Jorgen Lundman <lundman@lundman.net>
Signed-off-by: Matt Macy <mmacy@FreeBSD.org>
Closes #9556
2019-11-21 09:32:57 -08:00
Matthew Macy
d46f0deb03 Add wrapper for Linux BLKFLSBUF ioctl
FreeBSD has no analog. Buffered block devices were removed a decade
plus ago.

Reviewed-by: Igor Kozhukhov <igor@dilos.org>
Reviewed-by: Jorgen Lundman <lundman@lundman.net>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Matt Macy <mmacy@FreeBSD.org>
Closes #9508
2019-10-28 09:53:39 -07:00
Matthew Macy
8b2d097c17 Remove gratuitous Linux only include in ztest & zdb
We don't need to include stdio_ext.h

Reviewed-by: Igor Kozhukhov <igor@dilos.org>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Matt Macy <mmacy@FreeBSD.org>
Closes #9483
2019-10-19 17:08:19 -07:00
Paul Dagnelie
ca5777793e Reduce loaded range tree memory usage
This patch implements a new tree structure for ZFS, and uses it to 
store range trees more efficiently.

The new structure is approximately a B-tree, though there are some 
small differences from the usual characterizations. The tree has core 
nodes and leaf nodes; each contain data elements, which the elements 
in the core nodes acting as separators between its children. The 
difference between core and leaf nodes is that the core nodes have an 
array of children, while leaf nodes don't. Every node in the tree may 
be only partially full; in most cases, they are all at least 50% full 
(in terms of element count) except for the root node, which can be 
less full. Underfull nodes will steal from their neighbors or merge to 
remain full enough, while overfull nodes will split in two. The data 
elements are contained in tree-controlled buffers; they are copied 
into these on insertion, and overwritten on deletion. This means that 
the elements are not independently allocated, which reduces overhead, 
but also means they can't be shared between trees (and also that 
pointers to them are only valid until a side-effectful tree operation 
occurs). The overhead varies based on how dense the tree is, but is 
usually on the order of about 50% of the element size; the per-node 
overheads are very small, and so don't make a significant difference. 
The trees can accept arbitrary records; they accept a size and a 
comparator to allow them to be used for a variety of purposes.

The new trees replace the AVL trees used in the range trees today. 
Currently, the range_seg_t structure contains three 8 byte integers 
of payload and two 24 byte avl_tree_node_ts to handle its storage in 
both an offset-sorted tree and a size-sorted tree (total size: 64 
bytes). In the new model, the range seg structures are usually two 4 
byte integers, but a separate one needs to exist for the size-sorted 
and offset-sorted tree. Between the raw size, the 50% overhead, and 
the double storage, the new btrees are expected to use 8*1.5*2 = 24 
bytes per record, or 33.3% as much memory as the AVL trees (this is 
for the purposes of storing metaslab range trees; for other purposes, 
like scrubs, they use ~50% as much memory).

We reduced the size of the payload in the range segments by teaching 
range trees about starting offsets and shifts; since metaslabs have a 
fixed starting offset, and they all operate in terms of disk sectors, 
we can store the ranges using 4-byte integers as long as the size of 
the metaslab divided by the sector size is less than 2^32. For 512-byte
sectors, this is a 2^41 (or 2TB) metaslab, which with the default
settings corresponds to a 256PB disk. 4k sector disks can handle 
metaslabs up to 2^46 bytes, or 2^63 byte disks. Since we do not 
anticipate disks of this size in the near future, there should be 
almost no cases where metaslabs need 64-byte integers to store their 
ranges. We do still have the capability to store 64-byte integer ranges 
to account for cases where we are storing per-vdev (or per-dnode) trees, 
which could reasonably go above the limits discussed. We also do not 
store fill information in the compact version of the node, since it 
is only used for sorted scrub.

We also optimized the metaslab loading process in various other ways
to offset some inefficiencies in the btree model. While individual
operations (find, insert, remove_from) are faster for the btree than 
they are for the avl tree, remove usually requires a find operation, 
while in the AVL tree model the element itself suffices. Some clever 
changes actually caused an overall speedup in metaslab loading; we use 
approximately 40% less cpu to load metaslabs in our tests on Illumos.

Another memory and performance optimization was achieved by changing 
what is stored in the size-sorted trees. When a disk is heavily 
fragmented, the df algorithm used by default in ZFS will almost always 
find a number of small regions in its initial cursor-based search; it 
will usually only fall back to the size-sorted tree to find larger 
regions. If we increase the size of the cursor-based search slightly, 
and don't store segments that are smaller than a tunable size floor 
in the size-sorted tree, we can further cut memory usage down to 
below 20% of what the AVL trees store. This also results in further 
reductions in CPU time spent loading metaslabs.

The 16KiB size floor was chosen because it results in substantial memory 
usage reduction while not usually resulting in situations where we can't 
find an appropriate chunk with the cursor and are forced to use an 
oversized chunk from the size-sorted tree. In addition, even if we do 
have to use an oversized chunk from the size-sorted tree, the chunk 
would be too small to use for ZIL allocations, so it isn't as big of a 
loss as it might otherwise be. And often, more small allocations will 
follow the initial one, and the cursor search will now find the 
remainder of the chunk we didn't use all of and use it for subsequent 
allocations. Practical testing has shown little or no change in 
fragmentation as a result of this change.

If the size-sorted tree becomes empty while the offset sorted one still 
has entries, it will load all the entries from the offset sorted tree 
and disregard the size floor until it is unloaded again. This operation 
occurs rarely with the default setting, only on incredibly thoroughly 
fragmented pools.

There are some other small changes to zdb to teach it to handle btrees, 
but nothing major.
                                           
Reviewed-by: George Wilson <gwilson@delphix.com>
Reviewed-by: Matt Ahrens <matt@delphix.com>
Reviewed by: Sebastien Roy seb@delphix.com
Reviewed-by: Igor Kozhukhov <igor@dilos.org>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Paul Dagnelie <pcd@delphix.com>
Closes #9181
2019-10-09 10:36:03 -07:00
Andrea Gelmini
ad0b23b14a Fix typos in cmd/
Reviewed-by: Ryan Moeller <ryan@ixsystems.com>
Reviewed-by: Richard Laager <rlaager@wiktel.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Andrea Gelmini <andrea.gelmini@gelma.net>
Closes #9234
2019-08-30 09:43:30 -07:00