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* refs/pull/24158/head: cephfs: remove vestiges of mds deactivate Reviewed-by: Douglas Fuller <dfuller@redhat.com>
93 lines
2.7 KiB
ReStructuredText
93 lines
2.7 KiB
ReStructuredText
Upgrading the MDS Cluster
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=========================
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Currently the MDS cluster does not have built-in versioning or file system
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flags to support seamless upgrades of the MDSs without potentially causing
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assertions or other faults due to incompatible messages or other functional
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differences. For this reason, it's necessary during any cluster upgrade to
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reduce the number of active MDS for a file system to one first so that two
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active MDS do not communicate with different versions. Further, it's also
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necessary to take standbys offline as any new CompatSet flags will propagate
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via the MDSMap to all MDS and cause older MDS to suicide.
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The proper sequence for upgrading the MDS cluster is:
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1. Reduce the number of ranks to 1:
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::
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ceph fs set <fs_name> max_mds 1
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2. Wait for cluster to stop non-zero ranks where only rank 0 is active and the rest are standbys.
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::
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ceph status # wait for MDS to finish stopping
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3. Take all standbys offline, e.g. using systemctl:
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::
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systemctl stop ceph-mds.target
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4. Confirm only one MDS is online and is rank 0 for your FS:
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::
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ceph status
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5. Upgrade the single active MDS, e.g. using systemctl:
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::
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# use package manager to update cluster
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systemctl restart ceph-mds.target
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6. Upgrade/start the standby daemons.
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::
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# use package manager to update cluster
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systemctl restart ceph-mds.target
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7. Restore the previous max_mds for your cluster:
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::
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ceph fs set <fs_name> max_mds <old_max_mds>
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Upgrading pre-Firefly filesystems past Jewel
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============================================
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.. tip::
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This advice only applies to users with filesystems
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created using versions of Ceph older than *Firefly* (0.80).
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Users creating new filesystems may disregard this advice.
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Pre-firefly versions of Ceph used a now-deprecated format
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for storing CephFS directory objects, called TMAPs. Support
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for reading these in RADOS will be removed after the Jewel
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release of Ceph, so for upgrading CephFS users it is important
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to ensure that any old directory objects have been converted.
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After installing Jewel on all your MDS and OSD servers, and restarting
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the services, run the following command:
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::
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cephfs-data-scan tmap_upgrade <metadata pool name>
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This only needs to be run once, and it is not necessary to
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stop any other services while it runs. The command may take some
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time to execute, as it iterates overall objects in your metadata
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pool. It is safe to continue using your filesystem as normal while
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it executes. If the command aborts for any reason, it is safe
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to simply run it again.
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If you are upgrading a pre-Firefly CephFS filesystem to a newer Ceph version
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than Jewel, you must first upgrade to Jewel and run the ``tmap_upgrade``
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command before completing your upgrade to the latest version.
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