ASM Performance
- ASM will maximize the available bandwidth of disks by striping file extents across all disks in a DG
- Two stripe widths are available: coarse which has a stripe size of 1 AU, and fine with stripe size of 128K
- Fine striping still uses normally-sized file extents, but the striping occurs in small pieces across these extents in a round-robin fashion
- ASM does not read from alternating mirror copies since disks contain primary and mirror extents and I/O is already balanced
- By default the RDBMS will read from a primary extent; in 11.1 this can be changed via the PREFERRED_READ_FAILURE_GROUP parameter setting for cases where reading extents from a local node results in lower latency. Note: This is a special case applicable to “stretch clusters” and not applicable in the general usage of ASM
Responses