HP D5970A Integrated HP NetRaid Controller Configuration Guide - Page 43
Cached I/O, Direct I/O
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Chapter 4 Planning Cache Policy HP NetRAID lets you choose one of two cache policies: • Cached I/O: Reads are always cached regardless of randomness. The selected Read policy (Read-Ahead, Normal, or Adaptive) and Write policy (Write-Through and Write-Back) always applies. This is the default setting. • Direct I/O: First reads to a new location always come directly from the disk. If a location is read repeatedly, then the Read policy as selected will apply and the read data will be cached. Read data is cached only if accessed repeatedly. With 100% randomness, nothing is cached. For each logical drive, record the cache policy in Worksheet B. 37
Chapter 4
Planning
37
Cache Policy
HP NetRAID lets you choose one of two cache policies:
•
Cached I/O
: Reads are always cached regardless of randomness. The
selected Read policy (Read-Ahead, Normal, or Adaptive) and Write policy
(Write-Through and Write-Back) always applies. This is the default
setting.
•
Direct I/O
: First reads to a new location always come directly from the
disk. If a location is read repeatedly, then the Read policy as selected will
apply and the read data will be cached. Read data is cached only if
accessed repeatedly. With 100% randomness, nothing is cached.
For each logical drive, record the cache policy in Worksheet B.