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

Figure 23 LDEV Information pane
Deleting and remapping the external LU
You must delete and remap each LU that needs the cache setting changed. Using the information
recorded in Collecting device information, delete and remap each LDEV.
1. On the LU
Operation pane, select the appropriate external LU group number in the Device tree.
2. In the Device list, right-click the external LU that you want to delete, and select Delete LU (Figure 21).
3. Click Apply.
4. Click ei
ther Yes or No.IfyouclickYes, skip the next step.
5. Click OK in response to the warning message.
6. Click OK.
7. Remap t
he LU using all the previous settings except for the cache mode setting, which is disabled.
See Mapping external LUs (Add LU).
NOTE:
When scanning for devices to add, the order in which devices are discovered might be
different. The UUID is always the same for the same external device. Ensure that the UUID
of the device being remapped matches the UUID that was deleted for the same LU number.
8. Recheck to ensure that the same external storage LUs (identified by UUIDs) are now assigned their
original settings and the desired cache mode. If not, delete and remap the external LU again.
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:
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