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Brian Behlendorf 64bdf63f5c
ztest: split block reconstruction
Increase the default allowed number of reconstruction attempts.
There's not an exact right number for this setting.  It needs
to be set large enough to cover any realistic failure scenarios
and small enough to avoid stalling the IO pipeline and invoking
the dead man detection.

The current value of 256 was empirically determined to be too
low based on multi-day runs of ztest.  The fault injection code
would inject more damage than could be reconstructed given the
relatively small number of attempts.  However, in all observed
cases the block could be reconstructed using a slightly higher
limit.

Based on local testing increasing the default value to 4096 was
determined to strike the best balance.  Checking all combinations
takes less than 10s in the worst case, and has so far eliminated
the vast majority of false positives detected by ztest.  This
delay is roughly on par with how long retries may be performed
to a misbehaving HDD and was deemed to be reasonable.  Better to
err on the side of a brief delay rather than fail to reconstruct
the data.

Lastly, the -Y flag has been added to zdb to make it easy to try all
possible combinations when performing split block reconstruction.
For badly damaged blocks with 18 splits, they can be fully enumerated
within a few minutes.  This has been done to ensure permanent errors
are never incorrectly reported when ztest verifies the pool with zdb.

Reviewed by: Tom Caputi <tcaputi@datto.com>
Reviewed by: Matt Ahrens <mahrens@delphix.com>
Reviewed by: Serapheim Dimitropoulos <serapheim@delphix.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #8271
2019-01-16 14:10:02 -08:00
.github Bump commit subject length to 72 characters 2019-01-08 09:23:05 -08:00
cmd ztest: split block reconstruction 2019-01-16 14:10:02 -08:00
config pyzfs: python3 support (build system) 2019-01-06 10:39:41 -08:00
contrib Add contrib/pyzfs/setup.py to .gitignore 2019-01-13 10:04:38 -08:00
etc Add enclosure_symlinks option to vdev_id 2018-12-14 17:27:49 -08:00
include Serialize ZTHR operations to eliminate races 2019-01-13 10:09:46 -08:00
lib Include third party licenses in dist tarballs 2019-01-08 09:29:34 -08:00
man ztest: split block reconstruction 2019-01-16 14:10:02 -08:00
module ztest: split block reconstruction 2019-01-16 14:10:02 -08:00
rpm Add pyzfs BuildRequires for mock(1) 2019-01-13 10:02:33 -08:00
scripts Bump commit subject length to 72 characters 2019-01-08 09:23:05 -08:00
tests Make zdb results for checkpoint tests consistent 2019-01-16 10:41:47 -08:00
udev Add enclosure_symlinks option to vdev_id 2018-12-14 17:27:49 -08:00
.gitignore Verify .gitignore entries 2019-01-15 11:56:29 -08:00
.gitmodules Add zimport.sh compatibility test script 2014-02-21 12:10:31 -08:00
.travis.yml Add .travis.yml 2017-11-13 09:18:18 -08:00
AUTHORS Update build system and packaging 2018-05-29 16:00:33 -07:00
autogen.sh Cause autogen.sh to fail if autoreconf fails 2018-07-06 09:27:37 -07:00
configure.ac Use ZFS version for pyzfs & drop unused reqs file 2019-01-08 15:56:42 -08:00
copy-builtin Allow copy-builtin to work with modified sources 2018-10-17 12:06:05 -07:00
COPYRIGHT Update build system and packaging 2018-05-29 16:00:33 -07:00
LICENSE Update build system and packaging 2018-05-29 16:00:33 -07:00
Makefile.am Verify .gitignore entries 2019-01-15 11:56:29 -08:00
META Tag 0.8.0-rc3 2019-01-14 12:40:42 -08:00
NEWS Add NEWS file 2018-09-18 12:03:47 -07:00
NOTICE Update build system and packaging 2018-05-29 16:00:33 -07:00
README.md Explicitly state supported Linux versions 2018-05-30 20:11:19 -07:00
TEST Update build system and packaging 2018-05-29 16:00:33 -07:00
zfs.release.in Move zfs.release generation to configure step 2012-07-12 12:22:51 -07:00

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ZFS on Linux is an advanced file system and volume manager which was originally developed for Solaris and is now maintained by the OpenZFS community.

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Official Resources

Installation

Full documentation for installing ZoL on your favorite Linux distribution can be found at our site.

Contribute & Develop

We have a separate document with contribution guidelines.

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ZFS on Linux is released under a CDDL license.
For more details see the NOTICE, LICENSE and COPYRIGHT files; UCRL-CODE-235197

Supported Kernels

  • The META file contains the officially recognized supported kernel versions.