Network Hardware User Manual

U3585-J-Z125-8-76 287

SM2 reports PFA CACHE report

BLK SIZE Block size of the cache

SIZE Size of the cache

READ Number of read operations to hiperﬁles (in I/Os per second)

RD HIT Percentage of hits in the total number of read operations to hiper-

ﬁles

WRITE Number of write operations to hiperﬁles (in I/Os per second)

WR HIT Percentage of fast write operations in the total number of write

operations to hiperﬁles

OVERRUNS Number of unsuccessful attempts to use the cache due to overload

(per second)

Notes

– The number of read and write accesses is output to one decimal place. Read and write

rates less than 0.05 per second are rounded down to 0.0 per second and hit rates are

calculated.

– In SYMMETRIX controllers, all write operations are executed via the cache as fast

writes. An exception are delayed fast writes: if the cache is ﬁlled with unsaved write

data, these may be forced to wait temporarily for a cache slot to become available. A

WR HIT is one write operation that need not be delayed. Only very high write loads will

cause the WR HIT rate to fall below 100%. If this occurs, delayed fast writes will be

output under OVERRUNS.