HP StorageWorks 500 G2 Modular Smart Array - Manual (Page 22)

22 HP StorageWorks MSA500 G2 Storage System User Guide
NOTE: The data protection and the time limit also apply if a power
outage occurs. When power is restored to the system, an initialization
process writes the preserved data to the hard drives.
To enable faster data access from disk storage, the battery module performs two
types of caching:
• Posted-write caching—the controller writes user data in the cache memory
on the module rather than directly to the drives. Later, when the storage
system is idle, the controller writes the data to the drive array.
• Read-ahead caching—the controller detects sequential array access, reads
ahead into the next sequence of data, and stores the data in the read-ahead
cache. Then, if the next read access is for the cached data, the controller
immediately loads the data into system memory, avoiding the latency of a
disk access.
SCSI IDs
Bay SCSI ID Bus Port
1 0 0
2 1 0
3 2 0
4 3 0