[LUDOC-161] document backup/restore process for ZFS backing filesystems

• Type: Improvement
• Resolution: Fixed
• Priority: Major
• Labels: release
• Assignee: Lustre Manual Triage
• Reporter: Andreas Dilger

Description

The Lustre backup/restore documentation describes how to do a backup/restore using both "tar" and "dd" for ldiskfs devices. However, the preferred mechanism for backing up and restoring ZFS filesystems is via the "zfs send" and "zfs recv" mechanism. This will preserve the ZFS dnode numbers, and all of the FID->dnode mappings in the OI files. The zfs dump/restore functionality can also be used to do incremental backups, and keep two physically-separate devices in relatively close synchronization for disaster-recovery and other purposes.

It is also not currently possible to do a file-level backup from ldiskfs and restore this into a new ZFS filesystem because there is no OI Scrub facility for ZFS OSDs, so that should be documented as unsupported until LU-7585 is resolved.

Issue Links

• is related to: LUDOC-56 Add ZFS setup and formatting information
• is related to: LU-8124 MDT zpool capacity consumed at greater rate than inode allocation
• is related to: LU-9023 Second opinion on MDT inode recovery requested
• is related to: LU-7585 Implement OI Scrub for ZFS