Partitioning Cache For External Storage; For Example, Company A Uses; In Another Example, Company B Uses The Following Storage Tiers; To Partition Cache For External Storage - HP StorageWorks XP12000 User Manual

Partitioning cache for external storage

Separate cache partitions isolate the applications that are using XP arrays and storage virtualization
systems from the I/O dampening effects of a cache that is filling up with host and internal I/O for
slower external targets. HP requires separate cache partitions (CLPRs) for:
• External volumes and internal XP volumes, except for configurations where all external storage
LUNs have cache disabled and do not have any external storage devices using data mirroring or
migration products
NOTE:
All HP 200 Storage Virtualization System volumes are external. Partition SVS200 cache according
to the other recommendations made in this section.
• External volumes that are used by XP data replication or data migration products, including Business
Copy XP, Continuous Access XP software products, Snapshot XP, Auto LUN XP, and XP Tiered
Storage Manager
• SVS200 source volumes and data copy or target volumes that have slower throughput

For example, Company A uses:

• XP10000 internal disks for database applications
• EVA3000 for backup applications
Cache can be partitioned for Company A as follows:
• CLPR0: XP10000 for Business Copy XP P-VOL
• CLPR1: EVA3000 for Business Copy XP S-VOL (external LU cache is disabled)

In another example, Company B uses the following storage tiers:

• Tier 1 is an XP12000 (6 TB of internal space) for P-VOLs
• Tier 2 is an EVA (20 TB) for P-VOLs and Business Copy XP S-VOLs
• Tier 3 is two MSA 1500 (10 TB) for the Business Copy XP S-VOLs
Cache can be partitioned for Company B as follows:
• CLPR0: 12 GB for the internal XP12000 P-VOL
• CLPR1: 4 GB for the EVA S-VOL and P-VOL
• CLPR2: 4 GB for the MSA S-VOL
• All external LU cache is disabled.

To partition cache for external storage:

1.
Determine the number and size of the partitions you need (see
of needed
2. Create the partitions (see
partitions).
Creating cache
External Storage XP user guide for the XP12000, XP10000, SVS200
Determining the number and size
partitions).
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