[LU-17428] reduce default value for lru_max_age to 300s

• Type: Improvement
• Resolution: Fixed
• Priority: Minor
• Fix Version/s: Lustre 2.16.0
• Severity: 3
• Assignee: Andreas Dilger
• Reporter: Andreas Dilger

Description

The default value for lru_max_age is currently 3900s (3900000 msec), or 1h5m.

For most systems and use cases, this is far too long and can lead to clients holding on to locks that they don't need and may cause issues for other clients if those clients holding the LDLM locks have any network issues and the server lock callback RPCs are slow. It may also cause issues with the LRU, if clients hold on to locks only used once for a long time and potentially evict more important locks sooner, though more work is still needed to the DLM LRU algorithm in LU-11509.

We regularly tune ldlm.namespaces.*.lru_max_age=300s on large clusters, and it makes sense to change this to be the default.

Issue Links

• duplicates: LU-14517 Decrease default lru_max_age value
• is related to: LU-7266 Fix LDLM pool to make LRUR working properly
• is related to: LU-6402 reduce the value of LDLM_POOL_MAX_AGE
• is related to: LU-15630 recovery-small test_10a: no eviction: before:1646723217
• is related to: LU-18288 sanity test_120e: FAIL: 2 cancel RPC occured
• is related to: LU-6529 Server side lock limits to avoid unnecessary memory exhaustion
• is related to: LU-11509 LDLM: replace client lock LRU with improved cache algorithm
• is related to: LU-11092 NMI watchdog: BUG: soft lockup - CPU#12 stuck for 23s! [ptlrpcd_00_18:4222]