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4 Commits

Author SHA1 Message Date
George Wilson
619f097693 OpenZFS 9102 - zfs should be able to initialize storage devices
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/c3963210eb
Closes #8230
2019-01-07 10:37:26 -08:00
Matthew Ahrens
a1d477c24c OpenZFS 7614, 9064 - zfs device evacuation/removal
OpenZFS 7614 - zfs device evacuation/removal
OpenZFS 9064 - remove_mirror should wait for device removal to complete

This project allows top-level vdevs to be removed from the storage pool
with "zpool remove", reducing the total amount of storage in the pool.
This operation copies all allocated regions of the device to be removed
onto other devices, recording the mapping from old to new location.
After the removal is complete, read and free operations to the removed
(now "indirect") vdev must be remapped and performed at the new location
on disk.  The indirect mapping table is kept in memory whenever the pool
is loaded, so there is minimal performance overhead when doing operations
on the indirect vdev.

The size of the in-memory mapping table will be reduced when its entries
become "obsolete" because they are no longer used by any block pointers
in the pool.  An entry becomes obsolete when all the blocks that use
it are freed.  An entry can also become obsolete when all the snapshots
that reference it are deleted, and the block pointers that reference it
have been "remapped" in all filesystems/zvols (and clones).  Whenever an
indirect block is written, all the block pointers in it will be "remapped"
to their new (concrete) locations if possible.  This process can be
accelerated by using the "zfs remap" command to proactively rewrite all
indirect blocks that reference indirect (removed) vdevs.

Note that when a device is removed, we do not verify the checksum of
the data that is copied.  This makes the process much faster, but if it
were used on redundant vdevs (i.e. mirror or raidz vdevs), it would be
possible to copy the wrong data, when we have the correct data on e.g.
the other side of the mirror.

At the moment, only mirrors and simple top-level vdevs can be removed
and no removal is allowed if any of the top-level vdevs are raidz.

Porting Notes:

* Avoid zero-sized kmem_alloc() in vdev_compact_children().

    The device evacuation code adds a dependency that
    vdev_compact_children() be able to properly empty the vdev_child
    array by setting it to NULL and zeroing vdev_children.  Under Linux,
    kmem_alloc() and related functions return a sentinel pointer rather
    than NULL for zero-sized allocations.

* Remove comment regarding "mpt" driver where zfs_remove_max_segment
  is initialized to SPA_MAXBLOCKSIZE.

  Change zfs_condense_indirect_commit_entry_delay_ticks to
  zfs_condense_indirect_commit_entry_delay_ms for consistency with
  most other tunables in which delays are specified in ms.

* ZTS changes:

    Use set_tunable rather than mdb
    Use zpool sync as appropriate
    Use sync_pool instead of sync
    Kill jobs during test_removal_with_operation to allow unmount/export
    Don't add non-disk names such as "mirror" or "raidz" to $DISKS
    Use $TEST_BASE_DIR instead of /tmp
    Increase HZ from 100 to 1000 which is more common on Linux

    removal_multiple_indirection.ksh
        Reduce iterations in order to not time out on the code
        coverage builders.

    removal_resume_export:
        Functionally, the test case is correct but there exists a race
        where the kernel thread hasn't been fully started yet and is
        not visible.  Wait for up to 1 second for the removal thread
        to be started before giving up on it.  Also, increase the
        amount of data copied in order that the removal not finish
        before the export has a chance to fail.

* MMP compatibility, the concept of concrete versus non-concrete devices
  has slightly changed the semantics of vdev_writeable().  Update
  mmp_random_leaf_impl() accordingly.

* Updated dbuf_remap() to handle the org.zfsonlinux:large_dnode pool
  feature which is not supported by OpenZFS.

* Added support for new vdev removal tracepoints.

* Test cases removal_with_zdb and removal_condense_export have been
  intentionally disabled.  When run manually they pass as intended,
  but when running in the automated test environment they produce
  unreliable results on the latest Fedora release.

  They may work better once the upstream pool import refectoring is
  merged into ZoL at which point they will be re-enabled.

Authored by: Matthew Ahrens <mahrens@delphix.com>
Reviewed-by: Alex Reece <alex@delphix.com>
Reviewed-by: George Wilson <george.wilson@delphix.com>
Reviewed-by: John Kennedy <john.kennedy@delphix.com>
Reviewed-by: Prakash Surya <prakash.surya@delphix.com>
Reviewed by: Richard Laager <rlaager@wiktel.com>
Reviewed by: Tim Chase <tim@chase2k.com>
Reviewed by: Brian Behlendorf <behlendorf1@llnl.gov>
Approved by: Garrett D'Amore <garrett@damore.org>
Ported-by: Tim Chase <tim@chase2k.com>
Signed-off-by: Tim Chase <tim@chase2k.com>

OpenZFS-issue: https://www.illumos.org/issues/7614
OpenZFS-commit: https://github.com/openzfs/openzfs/commit/f539f1eb
Closes #6900
2018-04-14 12:16:17 -07:00
Tony Hutter
193a37cb24 Add -lhHpw options to "zpool iostat" for avg latency, histograms, & queues
Update the zfs module to collect statistics on average latencies, queue sizes,
and keep an internal histogram of all IO latencies.  Along with this, update
"zpool iostat" with some new options to print out the stats:

-l: Include average IO latencies stats:

 total_wait     disk_wait    syncq_wait    asyncq_wait  scrub
 read  write   read  write   read  write   read  write   wait
-----  -----  -----  -----  -----  -----  -----  -----  -----
    -   41ms      -    2ms      -   46ms      -    4ms      -
    -    5ms      -    1ms      -    1us      -    4ms      -
    -    5ms      -    1ms      -    1us      -    4ms      -
    -      -      -      -      -      -      -      -      -
    -   49ms      -    2ms      -   47ms      -      -      -
    -      -      -      -      -      -      -      -      -
    -    2ms      -    1ms      -      -      -    1ms      -
-----  -----  -----  -----  -----  -----  -----  -----  -----
  1ms    1ms    1ms  413us   16us   25us      -    5ms      -
  1ms    1ms    1ms  413us   16us   25us      -    5ms      -
  2ms    1ms    2ms  412us   26us   25us      -    5ms      -
    -    1ms      -  413us      -   25us      -    5ms      -
    -    1ms      -  460us      -   29us      -    5ms      -
196us    1ms  196us  370us    7us   23us      -    5ms      -
-----  -----  -----  -----  -----  -----  -----  -----  -----

-w: Print out latency histograms:

sdb           total           disk         sync_queue      async_queue
latency    read   write    read   write    read   write    read   write   scrub
-------  ------  ------  ------  ------  ------  ------  ------  ------  ------
1ns           0       0       0       0       0       0       0       0       0
...
33us          0       0       0       0       0       0       0       0       0
66us          0       0     107    2486       2     788      12      12       0
131us         2     797     359    4499      10     558     184     184       6
262us        22     801     264    1563      10     286     287     287      24
524us        87     575      71   52086      15    1063     136     136      92
1ms         152    1190       5   41292       4    1693     252     252     141
2ms         245    2018       0   50007       0    2322     371     371     220
4ms         189    7455      22  162957       0    3912    6726    6726     199
8ms         108    9461       0  102320       0    5775    2526    2526      86
17ms         23   11287       0   37142       0    8043    1813    1813      19
34ms          0   14725       0   24015       0   11732    3071    3071       0
67ms          0   23597       0    7914       0   18113    5025    5025       0
134ms         0   33798       0     254       0   25755    7326    7326       0
268ms         0   51780       0      12       0   41593   10002   10002       0
537ms         0   77808       0       0       0   64255   13120   13120       0
1s            0  105281       0       0       0   83805   20841   20841       0
2s            0   88248       0       0       0   73772   14006   14006       0
4s            0   47266       0       0       0   29783   17176   17176       0
9s            0   10460       0       0       0    4130    6295    6295       0
17s           0       0       0       0       0       0       0       0       0
34s           0       0       0       0       0       0       0       0       0
69s           0       0       0       0       0       0       0       0       0
137s          0       0       0       0       0       0       0       0       0
-------------------------------------------------------------------------------

-h: Help

-H: Scripted mode. Do not display headers, and separate fields by a single
    tab instead of arbitrary space.

-q: Include current number of entries in sync & async read/write queues,
    and scrub queue:

 syncq_read    syncq_write   asyncq_read  asyncq_write   scrubq_read
 pend  activ   pend  activ   pend  activ   pend  activ   pend  activ
-----  -----  -----  -----  -----  -----  -----  -----  -----  -----
    0      0      0      0     78     29      0      0      0      0
    0      0      0      0     78     29      0      0      0      0
    0      0      0      0      0      0      0      0      0      0
    -      -      -      -      -      -      -      -      -      -
    0      0      0      0      0      0      0      0      0      0
    -      -      -      -      -      -      -      -      -      -
    0      0      0      0      0      0      0      0      0      0
-----  -----  -----  -----  -----  -----  -----  -----  -----  -----
    0      0    227    394      0     19      0      0      0      0
    0      0    227    394      0     19      0      0      0      0
    0      0    108     98      0     19      0      0      0      0
    0      0     19     98      0      0      0      0      0      0
    0      0     78     98      0      0      0      0      0      0
    0      0     19     88      0      0      0      0      0      0
-----  -----  -----  -----  -----  -----  -----  -----  -----  -----

-p: Display numbers in parseable (exact) values.

Also, update iostat syntax to allow the user to specify specific vdevs
to show statistics for.  The three options for choosing pools/vdevs are:

Display a list of pools:
    zpool iostat ... [pool ...]

Display a list of vdevs from a specific pool:
    zpool iostat ... [pool vdev ...]

Display a list of vdevs from any pools:
    zpool iostat ... [vdev ...]

Lastly, allow zpool command "interval" value to be floating point:
    zpool iostat -v 0.5

Signed-off-by: Tony Hutter <hutter2@llnl.gov
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #4433
2016-05-12 12:36:32 -07:00
Paul Dagnelie
fcff0f35bd Illumos 5960, 5925
5960 zfs recv should prefetch indirect blocks
5925 zfs receive -o origin=
Reviewed by: Prakash Surya <prakash.surya@delphix.com>
Reviewed by: Matthew Ahrens <mahrens@delphix.com>

References:
  https://www.illumos.org/issues/5960
  https://www.illumos.org/issues/5925
  https://github.com/illumos/illumos-gate/commit/a2cdcdd

Porting notes:
- [lib/libzfs/libzfs_sendrecv.c]
  - b8864a2 Fix gcc cast warnings
  - 325f023 Add linux kernel device support
  - 5c3f61e Increase Linux pipe buffer size on 'zfs receive'
- [module/zfs/zfs_vnops.c]
  - 3558fd7 Prototype/structure update for Linux
  - c12e3a5 Restructure zfs_readdir() to fix regressions
- [module/zfs/zvol.c]
  - Function @zvol_map_block() isn't needed in ZoL
  - 9965059 Prefetch start and end of volumes
- [module/zfs/dmu.c]
  - Fixed ISO C90 - mixed declarations and code
  - Function dmu_prefetch() 'int i' is initialized before
    the following code block (c90 vs. c99)
- [module/zfs/dbuf.c]
  - fc5bb51 Fix stack dbuf_hold_impl()
  - 9b67f60 Illumos 4757, 4913
  - 34229a2 Reduce stack usage for recursive traverse_visitbp()
- [module/zfs/dmu_send.c]
  - Fixed ISO C90 - mixed declarations and code
  - b58986e Use large stacks when available
  - 241b541 Illumos 5959 - clean up per-dataset feature count code
  - 77aef6f Use vmem_alloc() for nvlists
  - 00b4602 Add linux kernel memory support

Ported-by: kernelOfTruth kerneloftruth@gmail.com
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
2016-01-08 15:08:19 -08:00