[LU-17250] Add new MDT to existing filesystem misses OST pools, nodemaps, and other config

• Type: Bug
• Resolution: Fixed
• Priority: Major
• Fix Version/s: Lustre 2.16.0
• Affects Version/s: Lustre 2.15.3
• Severity: 3
• Assignee: Etienne Aujames
• Reporter: Andreas Dilger

Description

If new MDTs are added to an existing filesystem that has OST Pools configured, the new MDTs are missing all of the configuration parameters that describe the pools. In fact, the new MDTs will also be missing any other persistent config parameters that are stored in the per-target config logs by "lctl conf_param", "lctl pool_*", "lctl nodemap_*", etc.

This issue does not apply to persistent parameters set with "lctl set_param -P", since this is a generic config log that is applied to all nodes and does not store specific configuration records into a per-target log.

It probably makes sense for the MGS to copy the config llog from another target (eg. fsname-MDT0000) to add these parameters to newly-added MDTs (and OSTs for that matter). The "regular" configuration records (attach, setup, add_uuid, new_profile, add_osc) should be skipped along with SKIP records, while conf_param, new_pool, add_pool, etc. records should be copied into the new target device log, with suitable replacements (eg. "s/MDT0000/MDTxxxx/").

Issue Links

• is related to: LU-17308 makes "lctl pool_*" more reliable for big configurations