HP StorageWorks External Storage XP user guide for the XP12000, XP10000, SVS200 (T1706-96009, October 2007)

• 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

• Tier2isanEVA(20TB)forP-VOLsandBusinessCopyXPS-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 Determining the number and size

of needed partitions).

2. Create the partitions (see Creating cache partitions).

Determining the number and size of needed partitions

The minimum cache partition (CLPR) size is 4 GB. Determine the size you need for each CLPR being

used for external storage based on the total capacity of the assigned external volumes. Table 6 shows

the recommended cache sizes for external storage CLPRs on open systems. Table 7 shows the same

information for HP storage virtualization systems.

Table 6 Recommended individual CLPR cache size for external storage on open systems

External storage volume capacity assigned to CLPR

Recommended cache size for CLPR

Less than 128,000 GB

4GB

128 ,0 0 0 G B o r m o re 8 G B

Managing cache with external storage