APC 15000 RAID User Manual
Controller Management
007-5510-002
61
Figure 3–33
System Performance Statistics Screen
Read Hits shows the percentage of Read I/O requests where the data was already in the cache. Prefetch
Hits shows the percentage of Read I/O requests where the data was already in the cache due to
prefetching. Prefetches shows the percentage of host Read I/O requests to the disks due to prefetching.
Hits shows the percentage of Read I/O requests where the data was already in the cache due to
prefetching. Prefetches shows the percentage of host Read I/O requests to the disks due to prefetching.
The bottom of the screen displays the Read and Write performance of the disks. Disk Pieces shows the
total number of disk I/O requests from the host ports. The system will combine several host I/O requests
into a single disk I/O request. The histogram at the lower right shows how often this is occurring for reads
and writes. BDB Pieces is the number of host I/O blocking and deblocking requests.
total number of disk I/O requests from the host ports. The system will combine several host I/O requests
into a single disk I/O request. The histogram at the lower right shows how often this is occurring for reads
and writes. BDB Pieces is the number of host I/O blocking and deblocking requests.
Cache Writeback Data shows the percentage of the cache which contains writeback data that must be
written to the disks. Cache Rebuild Data shows the percentage of the cache in use for rebuild operations.
Cache Data Lock shows the percentage of the cache which is locked by the locked LUNs.
written to the disks. Cache Rebuild Data shows the percentage of the cache in use for rebuild operations.
Cache Data Lock shows the percentage of the cache which is locked by the locked LUNs.
STATS CLEAR resets all the statistics back to zero.