Which record Size is optimal for sequential read and write I/O of any size, such as online redo log,
and large block random read and write I/O?
A.
8 KB
B.
64 KB
C.
128 KB
D.
256 KB
Explanation:
Example:After data has been prefetched, the application may then request it with its
own ARC accesses.
Note that the sizes may be different: prefetch may occur with a 128 Kbyte I/O size, while the
application may be reading with an 8 Kbyte I/O size. For example, the following doesn’t appear
directly related:
* data hits: 368
* prefetch data misses: 23
However it may be: if prefetch was requesting with a 128 KByte I/O size, 23 x 128 = 2944 Kbytes.
And if the application was requesting with an 8 Kbyte I/O size, 368 x 8 = 2944 Kbytes.
Note:Prefetch is a mechanism to improve the performance of streaming read workloads. It
examinesI/O activity to identify sequential reads, and can issue extra reads ahead of time so that
the datacan be in cache before the application requests it.
Sun ZFS Storage 7000 System Administration Guide, Prefetch