Storage Pooling - HP StorageWorks 12000 - Virtual Library System EVA Gateway Manual

• The EVA LUNs must be fully initialized and ready for use before attaching the VLS to the EVA. It
can take several hours to initialize an entire EVA; therefore, HP advises you to create the LUNs in
advance of the installation.
• 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 2047GB. 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 VLS12000 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 recom-
mends using a dedicated EVA for the VLS12000.

Storage Pooling

On the VLS12000 and VLS9000, 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
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 VLS12000 and VLS9000 must be done manually.
See Figure 47.
what is considered a catastrophic
HP StorageWorks VLS and D2D Solutions Guide 121