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Olaf Faaland 379ca9cf2b Multi-modifier protection (MMP)
Add multihost=on|off pool property to control MMP.  When enabled
a new thread writes uberblocks to the last slot in each label, at a
set frequency, to indicate to other hosts the pool is actively imported.
These uberblocks are the last synced uberblock with an updated
timestamp.  Property defaults to off.

During tryimport, find the "best" uberblock (newest txg and timestamp)
repeatedly, checking for change in the found uberblock.  Include the
results of the activity test in the config returned by tryimport.
These results are reported to user in "zpool import".

Allow the user to control the period between MMP writes, and the
duration of the activity test on import, via a new module parameter
zfs_multihost_interval.  The period is specified in milliseconds.  The
activity test duration is calculated from this value, and from the
mmp_delay in the "best" uberblock found initially.

Add a kstat interface to export statistics about Multiple Modifier
Protection (MMP) updates. Include the last synced txg number, the
timestamp, the delay since the last MMP update, the VDEV GUID, the VDEV
label that received the last MMP update, and the VDEV path.  Abbreviated
output below.

$ cat /proc/spl/kstat/zfs/mypool/multihost
31 0 0x01 10 880 105092382393521 105144180101111
txg   timestamp  mmp_delay   vdev_guid   vdev_label vdev_path
20468    261337  250274925   68396651780       3    /dev/sda
20468    261339  252023374   6267402363293     1    /dev/sdc
20468    261340  252000858   6698080955233     1    /dev/sdx
20468    261341  251980635   783892869810      2    /dev/sdy
20468    261342  253385953   8923255792467     3    /dev/sdd
20468    261344  253336622   042125143176      0    /dev/sdab
20468    261345  253310522   1200778101278     2    /dev/sde
20468    261346  253286429   0950576198362     2    /dev/sdt
20468    261347  253261545   96209817917       3    /dev/sds
20468    261349  253238188   8555725937673     3    /dev/sdb

Add a new tunable zfs_multihost_history to specify the number of MMP
updates to store history for. By default it is set to zero meaning that
no MMP statistics are stored.

When using ztest to generate activity, for automated tests of the MMP
function, some test functions interfere with the test.  For example, the
pool is exported to run zdb and then imported again.  Add a new ztest
function, "-M", to alter ztest behavior to prevent this.

Add new tests to verify the new functionality.  Tests provided by
Giuseppe Di Natale.

Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Reviewed-by: Giuseppe Di Natale <dinatale2@llnl.gov>
Reviewed-by: Ned Bass <bass6@llnl.gov>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Olaf Faaland <faaland1@llnl.gov>
Closes #745
Closes #6279
2017-07-13 13:54:00 -04:00
.github Provide links to info about ZFS Buildbot options 2017-06-15 17:52:18 -07:00
cmd Multi-modifier protection (MMP) 2017-07-13 13:54:00 -04:00
config Prevent dependencies on Debianized packages 2017-07-07 10:45:17 -07:00
contrib Fix initramfs hook for merged /usr/lib and /lib 2017-02-27 12:03:23 -08:00
etc zpool iostat/status -c improvements 2017-06-05 10:52:15 -07:00
include Multi-modifier protection (MMP) 2017-07-13 13:54:00 -04:00
lib Multi-modifier protection (MMP) 2017-07-13 13:54:00 -04:00
man Multi-modifier protection (MMP) 2017-07-13 13:54:00 -04:00
module Multi-modifier protection (MMP) 2017-07-13 13:54:00 -04:00
rpm zpool iostat/status -c improvements 2017-06-05 10:52:15 -07:00
scripts Multi-modifier protection (MMP) 2017-07-13 13:54:00 -04:00
tests Multi-modifier protection (MMP) 2017-07-13 13:54:00 -04:00
udev Fix spelling 2017-01-03 11:31:18 -06:00
.gitignore Improve gitignore 2017-05-25 10:14:13 -07:00
.gitmodules Add zimport.sh compatibility test script 2014-02-21 12:10:31 -08:00
AUTHORS Add a missing > to AUTHORS 2014-09-02 14:18:53 -07:00
autogen.sh build: do not call boilerplate ourself 2013-04-02 10:55:20 -07:00
configure.ac Multi-modifier protection (MMP) 2017-07-13 13:54:00 -04:00
copy-builtin Allow c99 when building ZFS in the kernel tree 2017-03-27 12:31:15 -07:00
COPYRIGHT Update ZED copyright boilerplate 2015-05-11 15:07:00 -07:00
DISCLAIMER Fix minor typos and update marketing copy. 2013-03-21 12:51:06 -07:00
Makefile.am Prebaked scripts for zpool status/iostat -c 2017-04-21 09:27:04 -07:00
META Tag 0.7.0-rc4 2017-05-05 10:33:40 -07:00
OPENSOLARIS.LICENSE Add CDDL license file 2008-12-01 14:49:34 -08:00
README.markdown Add CONTRIBUTING information and templates 2016-12-09 12:48:12 -07:00
TEST Retire filebench testing 2017-06-01 06:24:28 -07:00
zfs-script-config.sh.in zpool iostat/status -c improvements 2017-06-05 10:52:15 -07:00
zfs.release.in Move zfs.release generation to configure step 2012-07-12 12:22:51 -07:00

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

ZFS on Linux, which is also known as ZoL, is currently feature complete. It includes fully functional and stable SPA, DMU, ZVOL, and ZPL layers. And it's native!

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.