HP XP Array Manager Software - Manual (Page 16)

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The user has the option of pre-staging the data to the resident cache area. If pre-staging is
not used, the data will be loaded into the Cache Residency extents when the first miss occurs.
If pre-staging is used, performance may be affected for a short time while the data is read
into Cache Residency cache.
Note: Pre-staging of Cache Residency data should not be performed during peak activity.
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All write I/Os to Cache Residency data are duplex writes, guaranteeing full data integrity.
The Cache Residency data remains fixed in cache until the user manually deletes it. Deletion
of Cache Residency extents will destage any write data to the affected volume(s).
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It is possible to expand the amount of Cache Residency cache without canceling the existing
Cache Residency settings. Call HP technical support for assistance.
Table 3 Cache Residency Manager Specifications
Specifications Item
Mainframe: (zSeries and S/390) Open System
• 3380-3, 3A, 3B, 3C, F, K, KA, KB, KC
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3390-3, 3A, 3B, 3C, 3R, 9, 9A, 9B, 9C, L, LA,
LB, LC, M, MA, MB, MC
• NF80-F, K, KA, KB, KC
OPEN-3, 8, 9, E, L, V Emulation type
Virtual LVI (VLL) volume HP StorageWorks XP LUN
Expansion (LUSE) volume and Virtual
LUN (VLL) volume Supported
volumes
At least one cache slot (or track): Equivalent to 66
KB.
Up to 1 LDEV
For OPEN-V, at least 512 LBAs
(Logical Block Address): Equivalent
to 264 KB
For other than OPEN-V, at least 96
LBAs (Logical Block Address):
Equivalent to 66 KB
Unit of cache
area allocation
In Subsystem: 16,384
In LDEV: 4,096
Number of cache
areas
Cache Residency Manager Restrictions
The following are restrictions on the use of the Cache Residency function:
WARNING: Do not perform the XP Business Copy Software quick restore operation or the XP Auto
LUN Software operation on a Cache Residency volume. Also, do not specify the Cache Residency
setting on the volume where the XP Business Copy Software quick restore or the XP Auto LUN
Software operation is performed. These operations swap the internal locations of the source and
target volumes and this causes a loss of data integrity.
For additional information, see the HP StorageWorks XP24000/XP20000 Business Copy Software
User Guideand/or contact technical support.
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Do not attempt to allocate Cache Residency cache beyond the allocated capacity.
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Do not apply Cache Residency settings to volumes reserved for Auto LUN.
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Do not attempt to allocate Cache Residency cache redundantly over the cache area that is
already allocated to an LDEV.
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The Cache Residency bind mode is not available to external volumes whose Cache mode is
set to Disable (which is the mode that disables the use of the cache when there is an I/O
request from the host).
16 Preparing for Cache Residency Manager Operations