HP Insight Management Agents - Manual (Page 58)

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Caching Algorithm displays the caching algorithm currently in use for the cache volume. The
following values are valid:
◦ Unknown—Indicates that the Storage Agent is unable to determine the caching algorithm
for this cache volume. You may need to upgrade your software.
◦ Multi Segment—Indicates that multiple tiers to track cached and potentially cacheable
data are being used. The multi-segment cache takes into account frequency, spatial locality
and temporal locality of data accesses. The replacement policy is conservative making
the algorithm ideal for workloads that have a mixture of cacheable and non-cacheable
data with hot spots that remain hot for some time.
◦ Single Segment—Indicates that a single tier tracks cached data. The single-segment cache
takes into account spatial and temporal locality of data accesses. The replacement policy
is very aggressive resulting in the algorithm being ideal for workloads that have very few
non-cacheable data accesses and hotspots that move frequently.
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Cache State displays the current cache state of the cache volume. The following values are
valid:
◦ Unknown—Indicates that the Storage Agent is unable to determine the cache state for
this cache volume. You may need to upgrade your software.
◦ OK—Indicates that the cache volume is in normal operation mode and is fully functional.
◦ Degraded—Indicates that this cache volume is currently degraded with limited functionality.
◦ Cache Volume Offline—Indicates that the cache volume member is currently offline.
◦ Logical Drive Offline—Indicates that the logical drive member is currently offline.
◦ Never Configured—Indicates that the cache volume was never configured.
◦ Flushing—Indicates that cache data is currently flushing from DDR cache.
◦ Configuring—Indicates that cache is currently configuring.
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Write Policy displays the current write policy of the cache volume. The following values are
valid:
◦ Unknown—Indicates that the Storage Agent is unable to determine the write policy for
this cache volume. You may need to upgrade your software.
◦ Read Only—Indicates that this cache volume is currently using a read only policy.
◦ Write Through—Indicates that this cache volume is currently using a write through policy.
◦ Write Back Safe—Indicates that this cache volume is currently using a write back safe
policy. Writing is being executed to a cache volume that utilizes a redundant RAID level.
If the cache volume's redundancy becomes degraded, the cache volume will utilize the
write through write policy until redundancy is restored.
◦ Write Back Unsafe—Indicates that this cache volume is currently using a write back unsafe
policy. Writing is being executed to a cache volume that is not utilizing a redundant RAID
level.
◦ Write Through No Load—Indicates that this cache volume is currently using a write through
no load policy. The cache volume will process write requests but will only write if the line
is already loaded.
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Cache Line Size—Indicates the cache line size in number of blocks.
58 Agent information