Quantum 6-01376-05 manual StorNext File System Tuning Metadata Controller System

StorNext File System Tuning

The Metadata Controller System

It also possible to trigger an instant FSM statistics report by setting the Once Only debug flag using cvadmin. For example:

cvadmin -F snfs1 -e ‘debug 0x01000000’ ; tail -100 /usr/cvfs/data/snfs1/log/cvlog

The following items are a few things to watch out for:

•A non-zero value for FSM wait SUMMARY journal waits indicates insufficient IOPS performance of the disks assigned to the metadata stripe group. This usually requires reducing the metadata I/O latency time by adjusting RAID cache settings or reducing bandwidth contention for the metadata LUN. Another possible solution is to add another metadata stripe group to the file system. This will improve metadata ops performance through I/O concurrency.

•Non-zero value for FSM wait SUMMARY free buffer waits or low hit ratio for FSM cache SUMMARY buffer lookups indicates the FSM configuration setting BufferCacheSize is insufficient.

•Non-zero value for FSM wait SUMMARY free inode waits or low hit ratio for FSM cache SUMMARY inode lookups indicates the FSM configuration setting InodeCacheSize is insufficient.

•Large value for FSM threads SUMMARY max busy indicates the FSM configuration setting ThreadPoolSize is insufficient.

•Extremely high values for FSM cache SUMMARY inode lookups, TKN SUMMARY TokenRequestV3, or TKN SUMMARY TokenReqAlloc might indicate excessive file fragmentation. If so, the snfsdefrag utility can be used to fix the fragmented files.

•The VOP and TKN summary statistics indicate the count and avg/ min/max microsecond latency for the various metadata operations. This shows what type of metadata operations are most prevalent and most costly. These are also broken out per client, which can be useful to identify a client that is disproportionately loading the FSM.

SNFS supports the Windows Perfmon utility. This provides many useful statistics counters for the SNFS client component. To install, obtain a copy of cvfsperf.dll from the SCM team in Denver and copy it into the c:/ winnt/system32 directory on the SNFS client system. Then run rmperfreg.exe and instperfreg.exe to set up the required registry settings. After these steps, the SNFS counters should be visible to the Windows Perfmon utility. If not, check the Windows Application Event log for errors.

StorNext File System Tuning Guide 13