The short-path is now one access() call,
we always modprobe zfs (ZFS_MODULE_LOADING which doesn't use the libzfs
boolean parsing is gone),
and we use a simple inotify IN_CREATE loop with a timerfd timeout
rather than 10ms kernel-style polling
There's one substantial difference: ZFS_MODULE_TIMEOUT=-1
now means "never give up", rather than "wait 10 minutes"
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Ahelenia Ziemiańska <nabijaczleweli@nabijaczleweli.xyz>
Closes#13330
Update zpool.8 to avoid parseltongue.
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Reviewed-by: George Melikov <mail@gmelikov.ru>
Signed-off-by: Piotr P. Stefaniak <pstef@freebsd.org>
Closes#12763
This change updates the documentation to refer to the project
as OpenZFS instead ZFS on Linux. Web links have been updated
to refer to https://github.com/openzfs/zfs. The extraneous
zfsonlinux.org web links in the ZED and SPL sources have been
dropped.
Reviewed-by: George Melikov <mail@gmelikov.ru>
Reviewed-by: Richard Laager <rlaager@wiktel.com>
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#11007
There are a ton of zfs-* and zpool-* man pages. This adds them to
the SEE ALSO section so that people can more quickly look through
what all the options are, now that the pages have been split.
Reviewed-by: Richard Laager <rlaager@wiktel.com>
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Reviewed-by: George Melikov <mail@gmelikov.ru>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Allan Jude <allan@klarasystems.com>
Signed-off-by: John-Mark Gurney <jmg@funkthat.com>
Closes#10589
Many modern devices use physical allocation units that are much
larger than the minimum logical allocation size accessible by
external commands. Two prevalent examples of this are 512e disk
drives (512b logical sector, 4K physical sector) and flash devices
(512b logical sector, 4K or larger allocation block size, and 128k
or larger erase block size). Operations that modify less than the
physical sector size result in a costly read-modify-write or garbage
collection sequence on these devices.
Simply exporting the true physical sector of the device to ZFS would
yield optimal performance, but has two serious drawbacks:
1. Existing pools created with devices that have different logical
and physical block sizes, but were configured to use the logical
block size (e.g. because the OS version used for pool construction
reported the logical block size instead of the physical block
size) will suddenly find that the vdev allocation size has
increased. This can be easily tolerated for active members of
the array, but ZFS would prevent replacement of a vdev with
another identical device because it now appears that the smaller
allocation size required by the pool is not supported by the new
device.
2. The device's physical block size may be too large to be supported
by ZFS. The optimal allocation size for the vdev may be quite
large. For example, a RAID controller may export a vdev that
requires read-modify-write cycles unless accessed using 64k
aligned/sized requests. ZFS currently has an 8k minimum block
size limit.
Reporting both the logical and physical allocation sizes for vdevs
solves these problems. A device may be used so long as the logical
block size is compatible with the configuration. By comparing the
logical and physical block sizes, new configurations can be optimized
and administrators can be notified of any existing pools that are
sub-optimal.
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Co-authored-by: Matthew Macy <mmacy@freebsd.org>
Signed-off-by: Matt Macy <mmacy@FreeBSD.org>
Closes#10619
The recommended practice for `.Os` on FreeBSD is to not specify any
arguments. The correct OS name is used automatically.
Oddly enough, on the Linux distro I tested this on (CentOS 7), the man
pager defaulted to displaying "BSD" as the OS rather than "Linux". To
accommodate this, tack " Linux" back on in an install hook on Linux.
This is much simpler than removing it for FreeBSD when vendored in the
base system.
Reviewed-by: George Melikov <mail@gmelikov.ru>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Ryan Moeller <ryan@iXsystems.com>
Closes#10760
The horrible effects of human slavery continue to impact society. The
casual use of the term "slave" in computer software is an unnecessary
reference to a painful human experience.
This commit removes all possible references to the term "slave".
Implementation notes:
The zpool.d/slaves script is renamed to dm-deps, which uses the same
terminology as `dmsetup deps`.
References to the `/sys/class/block/$dev/slaves` directory remain. This
directory name is determined by the Linux kernel. Although
`dmsetup deps` provides the same information, it unfortunately requires
elevated privileges, whereas the `/sys/...` directory is world-readable.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Signed-off-by: Matthew Ahrens <mahrens@delphix.com>
Closes#10435
The corresponding zpool status option is -P and not -p. Update
this description to reference the correct option.
Reviewed-by: loli10K <ezomori.nozomu@gmail.com>
Reviewed-by: George Melikov <mail@gmelikov.ru>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#9803
If the ZFS_COLOR env variable is set, then use ANSI color
output in zpool status:
- Column headers are bold
- Degraded or offline pools/vdevs are yellow
- Non-zero error counters and faulted vdevs/pools are red
- The 'status:' and 'action:' sections are yellow if they're
displaying a warning.
This also includes a new 'faketty' function in libtest.shlib that is
compatible with FreeBSD (code provided by @freqlabs).
Reviewed-by: Jorgen Lundman <lundman@lundman.net>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Ryan Moeller <ryan@ixsystems.com>
Signed-off-by: Tony Hutter <hutter2@llnl.gov>
Closes#9340
Moved subcommand topics into individual manpages. Reordered and
grouped the list of subcommands by topic.
Moved concepts overview to `zpoolconcepts.8` and the long list of
available pool properties to `zpoolprops.8`.
Internal cross-references copied from `zpool.8` needed to be
converted to `.Xr` external references to new subcommand manual
pages.
Move `autotrim` into lexical order, autotrim tacked onto the end
of a list. Now it is in alphabetical order.
Clarify attach/detach description. Description was too specific to
command syntax. Overview clarifies reason for attaching or detaching
a device.
Clarify replace description, don't refer to subcommand arguments.
Clarify split command description, say what split actually does and
why you'd want to do it.
Clarify description of upgrade, and simplify the zpool.8 wording of
the zpool-upgrade(8) description.
Clarify description of import, detail what zpool-import(8) actually
does.
Add appropriate SEE ALSO sections. Divided zpool subcommand manual
pages need their own SEE ALSO sections. Also modified fsck.zfs.8
to point directly to zfs-scrub.8 and zed.8.in to include a direct
reference to zfs-events.8
Reviewed-by: Matt Ahrens <matt@delphix.com>
Reviewed-by: Kjeld Schouten <kjeld@schouten-lebbing.nl>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Ross Williams <ross@ross-williams.net>
Closes#9564
Since 0.7.0, zpool import would unconditionally block on udev for 30
seconds. This introduced a regression in initramfs environments that
lack udev (particularly mdev based environments), yet use a zfs userland
tools intended for the system that had been built against udev. Gentoo's
genkernel is the main example, although custom user initramfs
environments would be similarly impacted unless special builds of the
ZFS userland utilities were done for them. Such environments already
have their own mechanisms for blocking until device nodes are ready
(such as genkernel's scandelay parameter), so it is unnecessary for
zpool import to block on a non-existent udev until a timeout is reached
inside of them.
Rather than trying to intelligently determine whether udev is available
on the system to avoid unnecessarily blocking in such environments, it
seems best to just allow the environment to override the timeout. I
propose that we add an environment variable called
ZPOOL_IMPORT_UDEV_TIMEOUT_MS. Setting it to 0 would restore the 0.6.x
behavior that was more desirable in mdev based initramfs environments.
This allows the system user land utilities to be reused when building
mdev-based initramfs archives.
Reviewed-by: Igor Kozhukhov <igor@dilos.org>
Reviewed-by: Jorgen Lundman <lundman@lundman.net>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Georgy Yakovlev <gyakovlev@gentoo.org>
Signed-off-by: Richard Yao <ryao@gentoo.org>
Closes#9436
Currently the best way to wait for the completion of a long-running
operation in a pool, like a scrub or device removal, is to poll 'zpool
status' and parse its output, which is neither efficient nor convenient.
This change adds a 'wait' subcommand to the zpool command. When invoked,
'zpool wait' will block until a specified type of background activity
completes. Currently, this subcommand can wait for any of the following:
- Scrubs or resilvers to complete
- Devices to initialized
- Devices to be replaced
- Devices to be removed
- Checkpoints to be discarded
- Background freeing to complete
For example, a scrub that is in progress could be waited for by running
zpool wait -t scrub <pool>
This also adds a -w flag to the attach, checkpoint, initialize, replace,
remove, and scrub subcommands. When used, this flag makes the operations
kicked off by these subcommands synchronous instead of asynchronous.
This functionality is implemented using a new ioctl. The type of
activity to wait for is provided as input to the ioctl, and the ioctl
blocks until all activity of that type has completed. An ioctl was used
over other methods of kernel-userspace communiction primarily for the
sake of portability.
Porting Notes:
This is ported from Delphix OS change DLPX-44432. The following changes
were made while porting:
- Added ZoL-style ioctl input declaration.
- Reorganized error handling in zpool_initialize in libzfs to integrate
better with changes made for TRIM support.
- Fixed check for whether a checkpoint discard is in progress.
Previously it also waited if the pool had a checkpoint, instead of
just if a checkpoint was being discarded.
- Exposed zfs_initialize_chunk_size as a ZoL-style tunable.
- Updated more existing tests to make use of new 'zpool wait'
functionality, tests that don't exist in Delphix OS.
- Used existing ZoL tunable zfs_scan_suspend_progress, together with
zinject, in place of a new tunable zfs_scan_max_blks_per_txg.
- Added support for a non-integral interval argument to zpool wait.
Future work:
ZoL has support for trimming devices, which Delphix OS does not. In the
future, 'zpool wait' could be extended to add the ability to wait for
trim operations to complete.
Reviewed-by: Matt Ahrens <matt@delphix.com>
Reviewed-by: John Kennedy <john.kennedy@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: John Gallagher <john.gallagher@delphix.com>
Closes#9162
If dedup is in use, the `dedupditto` property can be set, causing ZFS to
keep an extra copy of data that is referenced many times (>100x). The
idea was that this data is more important than other data and thus we
want to be really sure that it is not lost if the disk experiences a
small amount of random corruption.
ZFS (and system administrators) rely on the pool-level redundancy to
protect their data (e.g. mirroring or RAIDZ). Since the user/sysadmin
doesn't have control over what data will be offered extra redundancy by
dedupditto, this extra redundancy is not very useful. The bulk of the
data is still vulnerable to loss based on the pool-level redundancy.
For example, if particle strikes corrupt 0.1% of blocks, you will either
be saved by mirror/raidz, or you will be sad. This is true even if
dedupditto saved another 0.01% of blocks from being corrupted.
Therefore, the dedupditto functionality is rarely enabled (i.e. the
property is rarely set), and it fulfills its promise of increased
redundancy even more rarely.
Additionally, this feature does not work as advertised (on existing
releases), because scrub/resilver did not repair the extra (dedupditto)
copy (see https://github.com/zfsonlinux/zfs/pull/8270).
In summary, this seldom-used feature doesn't work, and even if it did it
wouldn't provide useful data protection. It has a non-trivial
maintenance burden (again see https://github.com/zfsonlinux/zfs/pull/8270).
We should remove the dedupditto functionality. For backwards
compatibility with the existing CLI, "zpool set dedupditto" will still
"succeed" (exit code zero), but won't have any effect. For backwards
compatibility with existing pools that had dedupditto enabled at some
point, the code will still be able to understand dedupditto blocks and
free them when appropriate. However, ZFS won't write any new dedupditto
blocks.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Igor Kozhukhov <igor@dilos.org>
Reviewed-by: Alek Pinchuk <apinchuk@datto.com>
Issue #8270Closes#8310
Various changes (many by me) have been made to the man pages without
bumping their dates. I have now corrected them based on the last commit
to each file. I also added the script I used to make these changes.
Reviewed-by: Olaf Faaland <faaland1@llnl.gov>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Richard Laager <rlaager@wiktel.com>
Closes#8710
This standardizes the language on "deduplication tables" rather than
"dedup data" (which might be read as the data blocks rather than the
DDT). Likewise, it standardizes on "small file blocks". It also
standardizes on "normal" rather than using both "normal" and "general"
in the same paragraph. I also replaced "non-specified" with the more
explicit "non-dedup/special".
Reviewed-by: George Melikov <mail@gmelikov.ru>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Richard Laager <rlaager@wiktel.com>
Closes#8713
The 'zpool resilver' command requires that the resilver_defer
feature is active on the pool. Unfortunately, the check for
this was left out of the original patch. This commit simply
corrects this so that the command properly returns an error
in this case.
Reviewed by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Igor Kozhukhov <igor@dilos.org>
Signed-off-by: Tom Caputi <tcaputi@datto.com>
Closes#8700
Currently, it is possible for the 'zpool scrub' command to
progress slightly beyond 100% due to concurrent changes
happening on the live pool. This behavior is expected, but
the userspace code for 'zpool status' would subtract the
expected amount of data from the amount of data already
scrubbed, resulting in a negative integer being casted to a
large positive one. This number was then used to calculate
the estimated completion time, resulting in wildly wrong
results. This code changes the behavior so that 'zpool status'
does not attempt to report an estimate during this period.
Reviewed by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Igor Kozhukhov <igor@dilos.org>
Reviewed-by: George Melikov <mail@gmelikov.ru>
Signed-off-by: Tom Caputi <tcaputi@datto.com>
Closes#8611Closes#8687
This documents, in zpool.8, that dedupditto is deprecated and will be
made to have no effect in a future release.
Reviewed-by: George Melikov <mail@gmelikov.ru>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Matthew Ahrens <mahrens@delphix.com>
Signed-off-by: Richard Laager <rlaager@wiktel.com>
Closes#8650
It should only affect "zpool".
Reviewed-by: George Melikov <mail@gmelikov.ru>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Richard Laager <rlaager@wiktel.com>
Signed-off-by: Tomohiro Kusumi <kusumi.tomohiro@gmail.com>
Closes#8644
Add the 'zfs version' and 'zpool version' subcommands to display
the version of the user space utilities and loaded zfs kernel
module. For example:
$ zfs version
zfs-0.8.0-rc3_169_g67e0366b88
zfs-kmod-0.8.0-rc3_169_g67e0366b88
The '-V' and '--version' aliases were added to support the
common convention of using 'zfs --version` to obtain the version
information.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Matthew Ahrens <mahrens@delphix.com>
Reviewed-by: Richard Laager <rlaager@wiktel.com>
Signed-off-by: TerraTech <1118433+TerraTech@users.noreply.github.com>
Closes#2501Closes#8567
Previously, the "spare" vdev type was described as "A special
pseudo-vdev which...". I wanted to eliminate the word "special" from
that, now that the allocation_classes feature exists and there is such a
thing as a "special vdev". I ended up eliminating almost all instances
of the word "special" that are not referencing the allocation_classes
feature.
Reviewed-by: George Melikov <mail@gmelikov.ru>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Richard Laager <rlaager@wiktel.com>
Closes#8626
The macOS man app strenuously objects to blank lines in man files.
mdoc warning: Empty input line #xyz
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: bunder2015 <omfgbunder@gmail.com>
Reviewed-by: George Melikov <mail@gmelikov.ru>
Signed-off-by: Josh Soref <jsoref@users.noreply.github.com>
Closes#8559
UNMAP/TRIM support is a frequently-requested feature to help
prevent performance from degrading on SSDs and on various other
SAN-like storage back-ends. By issuing UNMAP/TRIM commands for
sectors which are no longer allocated the underlying device can
often more efficiently manage itself.
This TRIM implementation is modeled on the `zpool initialize`
feature which writes a pattern to all unallocated space in the
pool. The new `zpool trim` command uses the same vdev_xlate()
code to calculate what sectors are unallocated, the same per-
vdev TRIM thread model and locking, and the same basic CLI for
a consistent user experience. The core difference is that
instead of writing a pattern it will issue UNMAP/TRIM commands
for those extents.
The zio pipeline was updated to accommodate this by adding a new
ZIO_TYPE_TRIM type and associated spa taskq. This new type makes
is straight forward to add the platform specific TRIM/UNMAP calls
to vdev_disk.c and vdev_file.c. These new ZIO_TYPE_TRIM zios are
handled largely the same way as ZIO_TYPE_READs or ZIO_TYPE_WRITEs.
This makes it possible to largely avoid changing the pipieline,
one exception is that TRIM zio's may exceed the 16M block size
limit since they contain no data.
In addition to the manual `zpool trim` command, a background
automatic TRIM was added and is controlled by the 'autotrim'
property. It relies on the exact same infrastructure as the
manual TRIM. However, instead of relying on the extents in a
metaslab's ms_allocatable range tree, a ms_trim tree is kept
per metaslab. When 'autotrim=on', ranges added back to the
ms_allocatable tree are also added to the ms_free tree. The
ms_free tree is then periodically consumed by an autotrim
thread which systematically walks a top level vdev's metaslabs.
Since the automatic TRIM will skip ranges it considers too small
there is value in occasionally running a full `zpool trim`. This
may occur when the freed blocks are small and not enough time
was allowed to aggregate them. An automatic TRIM and a manual
`zpool trim` may be run concurrently, in which case the automatic
TRIM will yield to the manual TRIM.
Reviewed-by: Jorgen Lundman <lundman@lundman.net>
Reviewed-by: Tim Chase <tim@chase2k.com>
Reviewed-by: Matt Ahrens <mahrens@delphix.com>
Reviewed-by: George Wilson <george.wilson@delphix.com>
Reviewed-by: Serapheim Dimitropoulos <serapheim@delphix.com>
Contributions-by: Saso Kiselkov <saso.kiselkov@nexenta.com>
Contributions-by: Tim Chase <tim@chase2k.com>
Contributions-by: Chunwei Chen <tuxoko@gmail.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#8419Closes#598
When multihost is enabled, and a pool is suspended, return
EINVAL in response to "zpool clear <pool>". The pool
may have been imported on another host while I/O was suspended.
Reviewed-by: loli10K <ezomori.nozomu@gmail.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Olaf Faaland <faaland1@llnl.gov>
Closes#6933Closes#8460
Improve the man page text to warn the user about the risk of adding
the same device to multiple pools via simultaneous "zpool create",
"zpool add", "zpool replace", etc.
State that MMP/multihost does not protect against these scenarios.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: George Melikov <mail@gmelikov.ru>
Reviewed-by: Tony Hutter <hutter2@llnl.gov>
Signed-off-by: Olaf Faaland <faaland1@llnl.gov>
Closes#6473Closes#8457
In
-T u|d Display a time stamp. Specify -u for a printed
representation of the internal representation of time.
See time(2). Specify -d for standard date format.
See date(1).
'Specify u' and 'Specify d' should be used instead. `zpool list -T -u`
does not work.
Bring the descriptions in `zpool list` and `zpool status` in sync with
`zpool iostat`.
Reviewed by: Allan Jude <allanjude@freebsd.org>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Anatoly Borodin <anatoly.borodin@gmail.com>
Closes#8438
When `zpool iostat` fills the terminal the headers should be
printed again. `zpool iostat -n` can be used to suppress this.
If the command is not attached to a tty, headers will not be
printed so as to not break existing scripts.
Reviewed-by: Joshua M. Clulow <josh@sysmgr.org>
Reviewed-by: Giuseppe Di Natale <guss80@gmail.com>
Reviewed-by: George Melikov <mail@gmelikov.ru>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Tony Hutter <hutter2@llnl.gov>
Signed-off-by: Damian Wojsław <damian@wojslaw.pl>
Closes#8235Closes#8262
Only display the full details of the vdev initialization state
in 'zpool status' output when requested with the -i option.
By default display '(initializing)' after vdevs when they are
being actively initialized. This is consistent with the
established precident of appending '(resilvering), etc' and
fits within the default 80 column terminal width making it
easy to read.
Additionally, updated the 'zpool initialize' documentation to
make it clear the options are mutually exclusive, but allow
duplicate options like all other zfs/zpool commands.
Reviewed by: Matt Ahrens <mahrens@delphix.com>
Reviewed-by: loli10K <ezomori.nozomu@gmail.com>
Reviewed-by: Tim Chase <tim@chase2k.com>
Reviewed-by: George Wilson <george.wilson@delphix.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#8230
PROBLEM
========
The first access to a block incurs a performance penalty on some platforms
(e.g. AWS's EBS, VMware VMDKs). Therefore we recommend that volumes are
"thick provisioned", where supported by the platform (VMware). This can
create a large delay in getting a new virtual machines up and running (or
adding storage to an existing Engine). If the thick provision step is
omitted, write performance will be suboptimal until all blocks on the LUN
have been written.
SOLUTION
=========
This feature introduces a way to 'initialize' the disks at install or in the
background to make sure we don't incur this first read penalty.
When an entire LUN is added to ZFS, we make all space available immediately,
and allow ZFS to find unallocated space and zero it out. This works with
concurrent writes to arbitrary offsets, ensuring that we don't zero out
something that has been (or is in the middle of being) written. This scheme
can also be applied to existing pools (affecting only free regions on the
vdev). Detailed design:
- new subcommand:zpool initialize [-cs] <pool> [<vdev> ...]
- start, suspend, or cancel initialization
- Creates new open-context thread for each vdev
- Thread iterates through all metaslabs in this vdev
- Each metaslab:
- select a metaslab
- load the metaslab
- mark the metaslab as being zeroed
- walk all free ranges within that metaslab and translate
them to ranges on the leaf vdev
- issue a "zeroing" I/O on the leaf vdev that corresponds to
a free range on the metaslab we're working on
- continue until all free ranges for this metaslab have been
"zeroed"
- reset/unmark the metaslab being zeroed
- if more metaslabs exist, then repeat above tasks.
- if no more metaslabs, then we're done.
- progress for the initialization is stored on-disk in the vdev’s
leaf zap object. The following information is stored:
- the last offset that has been initialized
- the state of the initialization process (i.e. active,
suspended, or canceled)
- the start time for the initialization
- progress is reported via the zpool status command and shows
information for each of the vdevs that are initializing
Porting notes:
- Added zfs_initialize_value module parameter to set the pattern
written by "zpool initialize".
- Added zfs_vdev_{initializing,removal}_{min,max}_active module options.
Authored by: George Wilson <george.wilson@delphix.com>
Reviewed by: John Wren Kennedy <john.kennedy@delphix.com>
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Reviewed by: Pavel Zakharov <pavel.zakharov@delphix.com>
Reviewed by: Prakash Surya <prakash.surya@delphix.com>
Reviewed by: loli10K <ezomori.nozomu@gmail.com>
Reviewed by: Brian Behlendorf <behlendorf1@llnl.gov>
Approved by: Richard Lowe <richlowe@richlowe.net>
Signed-off-by: Tim Chase <tim@chase2k.com>
Ported-by: Tim Chase <tim@chase2k.com>
OpenZFS-issue: https://www.illumos.org/issues/9102
OpenZFS-commit: https://github.com/openzfs/openzfs/commit/c3963210ebCloses#8230
* Detect IO errors during device removal
While device removal cannot verify the checksums of individual
blocks during device removal, it can reasonably detect hard IO
errors from the leaf vdevs. Failure to perform this error
checking can result in device removal completing successfully,
but moving no data which will permanently corrupt the pool.
Situation 1: faulted/degraded vdevs
In the configuration shown below, the removal of mirror-0 will
permanently corrupt the pool. Device removal will preferentially
copy data from 'vdev1 -> vdev3' and from 'vdev2 -> vdev4'. Which
in this case will result in nothing being copied since one vdev
in each of those groups in unavailable. However, device removal
will complete successfully since all IO errors are ignored.
tank DEGRADED 0 0 0
mirror-0 DEGRADED 0 0 0
/var/tmp/vdev1 FAULTED 0 0 0 external fault
/var/tmp/vdev2 ONLINE 0 0 0
mirror-1 DEGRADED 0 0 0
/var/tmp/vdev3 ONLINE 0 0 0
/var/tmp/vdev4 FAULTED 0 0 0 external fault
This issue is resolved by updating the source child selection
logic to exclude unreadable leaf vdevs. Additionally, unwritable
destination child vdevs which can never succeed are skipped to
prevent generating a large number of write IO errors.
Situation 2: individual hard IO errors
During removal if an unexpected hard IO error is encountered when
either reading or writing the child vdev the entire removal
operation is cancelled. While it may be possible to reconstruct
the data after removal that cannot be guaranteed. The only
strictly safe thing to do is to cancel the removal.
As a future improvement we may want to instead suspend the removal
process and allow the damaged region to be retried. But that work
is left for another time, hard IO errors during the removal process
are expected to be exceptionally rare.
Reviewed-by: Serapheim Dimitropoulos <serapheim@delphix.com>
Reviewed-by: Tony Hutter <hutter2@llnl.gov>
Reviewed-by: Tom Caputi <tcaputi@datto.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #6900Closes#8161
