HP StorageWorks Performance Advisor XP Software user guide (T1789-96025, October 2007)

Cache logical partitions (CLPRs)
When one disk array is shared with multiple hosts, and one host reads or writes a large amount of data,
the host’s read
and write data occupies a large area in the disk array’s cache memory. In this situation,
the I/O perform
ance of other hosts decreases because the hosts must wait to write to cache memory. To
prevent this situation, CLPR partitions the disk array’s cache memory. Partitioned cache memories are
used as virtual cache memories, and each is allocated to each host. This approach minimizes the effects
of one adminis
trator’s operations on the volumes of other administrators.
Figure 57 Example of a CLPR
Example of a CLPR shows how a corporation’s cache memory is partitioned to three virtual cache
memories. Although the Branch A host is inputting and outputting a large amount of data, the Branch B
and Branch C hosts are unaffected because each branch is allocated 40 G B CLPR.
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Appendix A