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Brian Behlendorf
a65bb7c518
As part of SPA_LOAD_IMPORT add an additional activity check to
detect simultaneous imports from different hosts. This check is
only required when the timing is such that there's no activity
for the the read-only tryimport check to detect. This extra
safety chceck operates as follows:
1. Repeats the following MMP check 10 times:
a. Write out an MMP uberblock with the best txg and a random
sequence id to all primary pool vdevs.
b. Verify a minimum number of good writes such that even if
the pool appears degraded on the remote host it will see
at least one of the updated MMP uberblocks.
c. Wait for the MMP interval this leaves a window for other
racing hosts to make similar modifications which can be
detected.
d. Call vdev_uberblock_load() to determine the best uberblock
to use, this should be the MMP uberblock just written.
e. Verify the txg and random sequeunce number match the MMP
uberblock written in 1a.
2. Restore the original MMP uberblocks. This allows the check
to be performed again if the pool fails to import for an
unrelated reason.
This change also includes some refactoring and minor improvements.
- Never try loading earlier txgs during import when the import
fails with EREMOTEIO or EINTER. These errors don't indicate
the txg is damaged but instead that its either in use on a
remote host or the import was interactively cancelled. No
rewind is also performed for EBADD which can result from a
stale trusted config when doing a verbatim import.
- Refactor the code for consistent logging of the multihost
activity check using spa_load_note() and console messages
indicating when the activity check was trigger and the result.
- Added MMP_*_MASK and MMP_SEQ_CLEAR() macros to allow easier
modification of the sequence number in an uberblock.
- Added ZFS_LOAD_INFO_DEBUG environment variable which can be
set to log to dump to stdout the spa_load_info nvlist returned
during import. This is used by the updated mmp test cases
to determine if an activity check was run and its result.
- Standardize the mmp messages similarly to make it easier to
find all the relevent mmp lines in the debug log.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Tony Hutter <hutter2@llnl.gov>
Reviewed-by: Olaf Faaland <faaland1@llnl.gov>
Reviewed-by: Akash B <akash-b@hpe.com>
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.
Official Resources
- Documentation - for using and developing this repo
- ZoL Site - Linux release info & links
- Mailing lists
- OpenZFS site - for conference videos and info on other platforms (illumos, OSX, Windows, etc)
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
METAfile contains the officially recognized supported Linux kernel versions. - Supported FreeBSD versions are any supported branches and releases starting from 13.0-RELEASE.