Storage Pooling - HP 12000 Design Manual

Ensure that all VRaid LUNs required for the VLS have been created on the EVA such that the
LUNs are RAID 6 (preferred) or RAID 5, are not configured as read-only, and are roughly the
same size.
The maximum supported EVA LUN size is 2047 GB. Do not create LUNs for the VLS larger
than this even if the EVA model supports it.
On the EVA 8000, there are 4 Fibre Channel ports per controller which allows up to eight
paths to each LUN; however, configuring more than four paths per LUN will limit the maximum
capacity of the device without adding performance benefits. For this reason, HP recommends
use of only four paths per LUN.
It is possible to share an EVA between the VLS12X00 and other applications. If the EVA is
shared, VLS traffic may overwhelm the array and significantly reduce performance across all
applications sharing the array. Alternately, the other applications may slow down the
performance of the VLS. If this happens, manual load-balancing between applications is
required (that is, you will have to schedule the VLS traffic only when all other applications are
inactive). For this reason, HP recommends using a dedicated EVA for the VLS12X00.

Storage Pooling

On the VLS12X00 and VLS9X00, physical disk capacity can be separated into storage pools.
Virtual tapes can then be assigned to a specific storage pool. Having multiple storage pools allows
you to:
Minimize the impact if multiple disks fail at the same time — what is considered a catastrophic
array failure. If a catastrophic array failure destroys one or more LUNs on an array, only the
storage pool containing that array loses its data; all others retain their data.
Keep specific backup data physically separate from other backup data. For example, businesses
can keep data from one customer separate from that of another customer, or data from different
organizations can be kept separate.
Despite the benefits of creating multiple storage pools, maintenance is easier on a system with
only one storage pool because the VLS balances performance automatically for a single pool.
Load balancing the backup jobs across the pools with the VLS12X00 and VLS9X00 must be done
manually. See Figure 22 (page 60).
Implementation 59