Abends while using NSS Pool snapshotting

After upgrading to NetWare 6.5 Support Pack 8 the server started abending while backing up pool snapshots. 

Pool snapshots created for each pool on each server every night and snapshot deleted every night after backup.

Solution 1.

Increase the amount of a snapshot cache buffers it can use.

set Max Snapshot Cache Buffers = 440000
This allows for a larger pool of cache buffers limiting the possibility of seeing a problem.

 

Solution 2.

Apply the MM.NLM (Media Manager) update.
Patch may be downloaded using patch finder.  
Select Product: NetWare
Version: NetWare 6.5 SP8
Keyword: mm.nlm
Results:
Media Manager Update for NetWare 6.5 SP8

Abend: Deadlock detected waiting for spinlock currently owned by CPU ║0

Current EIP: 0010FA12  LOADER.NLM|WaitForSpinLock+62
8AE17D74  0010F83D  LOADER.NLM|kspinlock_patch+76
8AE17D78  80363A4F  MM.NLM|GetMappedBlock+197
8AE17DF0  80363777  MM.NLM|GetNextMappedBlockLevel+27
8AE17E00  80362980  MM.NLM|ReadMapBlockCallback+30
8AE17E1C  803224CD  MM.NLM|MM_CompleteMessage+35

 

Abend: CPU Hog Detected by Timer

LOADER.NLM|WaitForSpinLock
MM.NLM|GetMappedBlock+197

 

Code was added in NetWare 6.5 Support Pack 8 MM.NLM code to handle it's own memory caching.

Three new set parameters were added to manage this cache.

 

Max Free Snapshot Cache Buffers: 128

Limits: 32 to 2048

Description: Sets maximum number of cache buffers in the available list.

 

Alloc Snapshot Cache Buffers: 64

Limits: 16 to 128

Description: Sets number of snapshot cache buffers allocated each time.

Max Snapshot Cache Buffers: 2500

Limits: 128 to 44000

Description: Sets maximum number of cache buffers (4.6 K) allocated to snapshot.