Vls Warm Failover; Storage Pool Load Balancing On The Vls - HP StorageWorks 12000 - Virtual Library System EVA Gateway Manual

Figure 45 Storage Pool Load Balancing on the VLS
.
As Figure 45 shows, the VLS storage pool:
• Provides clustered virtual cartridge file system across one or more arrays.
• Automatically load-balances incoming backup data across all available array LUNs (in 32MB
extents).
• Prevents performance and capacity hot-spots.
If a virtual cartridge is overwritten by the backup application (e.g., because it reached the end of the
retention period and was reused for new backups), all of its existing blocks are freed up and then
new writes are dynamically assigned array LUNs as usual. When a new array is added to the VLS,
the load balancing system will automatically start using this new storage on subsequent virtual cartridge
writes (i.e., backups performed after the array was added will automatically load balance across all
storage including the new array). Any existing data that was present before the new array was added
will be rebalanced as virtual cartridges are recycled/expired and then overwritten by the backup
application.

VLS Warm Failover

A VLS feature (in firmware version 3.2 or higher) provides an automatic mechanism for faster recovery
from node0 failures, which is the ability to automatically restore the previous virtual library configuration
and licenses after a complete node0 replacement. This warm failover feature works as follows:
114 Virtual Library Systems