Breaking News: Messaging Server 6.3 and ZFS
By joesciallo on Sep 11, 2007
It's official! Messaging Server 6.3 now supports the ZFS file system, with the following caveats:
- You must patch Messaging Server 6.3 to 6.3p3 (6.3-4.01)). This patch has been released to SunSolve and should show up the week of September 10. See below for patch IDs.
- You must be running a minimum of Solaris OS 10 U3 for Messaging Server 6.3 to support ZFS.
- ZFS support does not apply to Linux platforms.
- Do not perform a ZFS snapshot when the message store database snapshot is running. Schedule ZFS snapshot to run 30 minutes after a message store database snapshot is run. This will allow the database snapshot to complete before the ZFS snapshot. Message store database snapshot frequency is controlled by local.snapshot.interval.
- Before restoring a ZFS snapshot make sure all Messaging Server processes are stopped.
If you want to backup your Message Store for disaster recovery, you can use a file system snapshot tool such as ZFS snapshot to capture a snapshot of the file system. The file system snapshot must be an atomic point-in-time snapshot (as is the case of ZFS), otherwise, the backup can have inconsistent data.
It is best to capture all message store data (message store partitions and database files) with the same file system snapshot instance. However, if this cannot be done, then capture the data in separate file system snapshots at the same time. And if this can't be done, capture the message store data in separate file system snapshots in the following order:
- Message store database snapshots. Note that database snapshots (configured with local.store.snapshotpath) are different from file system snapshots.
- Database files (data-root/store/mboxlist)
- Message store partition paths (store.partition.\*.path)
- Message store partition message paths (store.partition.\*.messagepath)
- Configuration data (data-root/config)
If the partitions and the database files are not backed up with the same point-in-time snapshot, run reconstruct -m after restoring the file system snapshots. This will synchronize the database and store partitions. Again, it is best to capture all message store data with the same file system snapshot instance to avoid doing a reconstruct.
If the message store database snapshot (db snapshot) is running when the file system snapshot is taken, the file system snapshot can contain an incomplete db snapshot. Although an incomplete db snapshot is harmless, it is best to schedule the file system snapshot to run 30 minutes after the db snapshot. This will ensure that a complete db snapshot is included in the file system snapshot.