Design Considerations; Performance - HP StorageWorks 12000 - Virtual Library System EVA Gateway Manual

2. Use the backup application to reformat/erase the cartridges identified by the Cartridge Utilization
Report as good candidates to free up disk space. For example, in Netbackup you can expire
and relabel the cartridges, in Data Protector you can recycle and format the cartridges, and in
TSM and NetWorker you can relabel the cartridges. In the backup application, you may need
to re-enable tape drives that were offlined or verify media that was marked as Poor because
backups were disabled in the VLS.
3. In the VLS GUI, use the Reclaim Space task in the Chassis pane to initiate an immediate space
reclamation (to free up the disk space on the reformatted/erased cartridges). A "Space
Reclamation is scheduled" notification is displayed on the notification screen.
4. If the VLS disk capacity drops below 90% utilization (due to reformatting/erasing cartridges and
reclaiming that disk space), backup writes are automatically re-enabled in the VLS. However, if
you need to re-enable writes with a disk utilization above 90% (and below 98%), use the VLS
GUI option Enable Writes in the Chassis pane to do this.

Design Considerations

Because every enterprise backup environment is different, there is no single answer for optimizing
deduplication. This section discusses deduplication design considerations to help you maximize
performance in your environment.
For guidelines based on your specific backup application, see ???.

Performance

Because the various phases of deduplication may be distributed among nodes, you must determine
how many nodes are necessary to optimize the performance in your environment. The following
concepts can help you determine this.
1. The ingest rate of backups, which is the amount of data that is backed up within the backup
window.
2. The number of nodes required for the maximum ingest rate.
For example, if your nightly backup consists of 40 TB to complete in eight hours at 5 TB per hour
(1388 MB per second) ingest rate, each node can ingest 500 MB per second. Therefore, three
nodes are required for this backup job.
3. Maximum daily deduplication limit per node.
For example, if 15 TB can be deduplicated in 24 hours by one node, deduplication of 40 TB
per day requires three nodes.
NOTE:
If the number of nodes required for backing up data differs from the number of nodes required
to perform deduplication, select the larger number of nodes.
NOTE:
On the VLS6200, do not enable software compression and deduplication together. Enabling software
compression will drastically reduce the performance if deduplication is enabled.
HP StorageWorks VLS and D2D Solutions Guide 157