
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 m em ories are
used as virtual c ache 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 56 Example of a CLPR
Example of a CLPR shows how a corporation’s cache memor y 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 GB CLPR.
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Appendix
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