Disk I/O characteristics for IBM Storage Protect operations

Generally, IBM Storage Protect storage pools are written to and read from by using I/O sizes of 256 KB.

With page sizes of 8 KB and 32 KB, the I/O that is used by the IBM Storage Protect database varies. The database manager might, at times, prefetch larger amounts.

While IBM Storage Protect might request the 8 KB and 32 KB I/O sizes, the operating system might choose to run I/O differently. Running the I/O differently can result in smaller or larger I/O being sent to the disk system.

IBM Storage Protect tries to use direct I/O in most situations, which avoids the file system cache. The result of avoiding the cache is better processor efficiency and performance. If you use operating system parameters to tune the file system cache, you might notice no effect for this reason.