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Brian Behlendorf ad8b9f940c
Scrub mirror children without BPs
When scrubbing a raidz/draid pool, which contains a replacing or
sparing mirror with multiple online children, only one child will
be read.  This is not normally a serious concern because the DTL
records are used to determine where a good copy of the data is.
As long as the data can be read from one child the mirror vdev
will use it to repair gaps in any of its children.  Furthermore,
even if the data which was read is corrupt the raidz code will
detect this and issue its own repair I/O to correct the damage
in the mirror vdev.

However, in the scenario where the DTL is wrong due to silent
data corruption (say due to overwriting one child) and the scrub
happens to read from a child with good data, then the other damaged
mirror child will not be detected nor repaired.

While this is possible for both raidz and draid vdevs, it's most
pronounced when using draid.  This is because by default the zed
will sequentially rebuild a draid pool to a distributed spare,
and the distributed spare half of the mirror is always preferred
since it delivers better performance.  This means the damaged
half of the mirror will go undetected even after scrubbing.

For system administrations this behavior is non-intuitive and in
a worst case scenario could result in the only good copy of the
data being unknowingly detached from the mirror.

This change resolves the issue by reading all replacing/sparing
mirror children when scrubbing.  When the BP isn't available for
verification, then compare the data buffers from each child.  They
must all be identical, if not there's silent damage and an error
is returned to prompt the top-level vdev to issue a repair I/O to
rewrite the data on all of the mirror children.  Since we can't
tell which child was wrong a checksum error is logged against the
replacing or sparing mirror vdev.

Reviewed-by: Mark Maybee <mark.maybee@delphix.com>
Reviewed-by: Tony Hutter <hutter2@llnl.gov>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #13555
2022-06-23 10:36:28 -07:00
.github Replace EXTRA_DIST with dist_noinst_DATA 2022-05-26 09:24:50 -07:00
cmd Replace ZPROP_INVAL with ZPROP_USERPROP where it means a user property 2022-06-14 11:27:53 -07:00
config Fix clang 13 compilation errors 2022-06-15 14:20:28 -07:00
contrib Remove install of zfs-load-module.service for dracut 2022-06-21 10:37:20 -07:00
etc Add weekly and monthly systemd timers for trimming 2022-06-10 18:22:14 -07:00
include Fix memory allocation issue for BLAKE3 context 2022-06-21 14:32:09 -07:00
lib libzfs: Prevent overridding of error code 2022-06-15 14:26:12 -07:00
man Add weekly and monthly systemd timers for trimming 2022-06-10 18:22:14 -07:00
module Scrub mirror children without BPs 2022-06-23 10:36:28 -07:00
rpm Replace EXTRA_DIST with dist_noinst_DATA 2022-05-26 09:24:50 -07:00
scripts Replace EXTRA_DIST with dist_noinst_DATA 2022-05-26 09:24:50 -07:00
tests Scrub mirror children without BPs 2022-06-23 10:36:28 -07:00
udev udev: zvol_id: simplify/modernise 2022-05-11 10:58:19 -07:00
.editorconfig Add an .editorconfig; document git whitespace settings 2020-01-27 13:32:52 -08:00
.gitignore autoconf: use include directives instead of recursing down cmd 2022-05-10 10:18:38 -07:00
.gitmodules .gitmodules: link to openzfs github repository 2021-04-12 09:37:23 -07:00
AUTHORS Introduce BLAKE3 checksums as an OpenZFS feature 2022-06-08 15:55:57 -07:00
autogen.sh autogen.sh: paper over automake <1.14's lack of %reldir% support 2022-05-10 10:20:46 -07:00
CODE_OF_CONDUCT.md Replace ZFS on Linux references with OpenZFS 2020-10-08 20:10:13 -07:00
configure.ac Switch sed -E to -r for better portability 2022-05-25 09:13:51 -07:00
copy-builtin copy-builtin: add hooks with sed/>> 2022-05-10 10:17:43 -07:00
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LICENSE Update build system and packaging 2018-05-29 16:00:33 -07:00
Makefile.am Replace EXTRA_DIST with dist_noinst_DATA 2022-05-26 09:24:50 -07:00
META Linux 5.18 compat: META 2022-05-31 14:38:00 -07:00
NEWS Fix NEWS file 2020-08-26 21:44:41 -07:00
NOTICE Update build system and packaging 2018-05-29 16:00:33 -07:00
README.md README: Update OpenZFS website url 2022-01-06 16:25:01 -08:00
RELEASES.md Add RELEASES.md file 2021-04-02 16:33:40 -07:00
TEST Remove CI builder customization from TEST 2020-03-16 10:46:03 -07:00
zfs.release.in Move zfs.release generation to configure step 2012-07-12 12:22:51 -07:00

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OpenZFS is an advanced file system and volume manager which was originally developed for Solaris and is now maintained by the OpenZFS community. This repository contains the code for running OpenZFS on Linux and FreeBSD.

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Official Resources

Installation

Full documentation for installing OpenZFS on your favorite operating system can be found at the Getting Started Page.

Contribute & Develop

We have a separate document with contribution guidelines.

We have a Code of Conduct.

Release

OpenZFS 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 Linux kernel versions.
  • Supported FreeBSD versions are any supported branches and releases starting from 12.2-RELEASE.