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1.
Use the VLS GUI to generate a Cartridge Utilization report (via Notifications Report Setup).
This report lists the barcode of each cartridge, disk space usage in bytes, deduplication status,
and dependent cartridges (if any) which can be used to identify the cartridges that you can
reformat/erase to create free storage. For example, first reformat/erase cartridges that are
consuming a considerable amount of space and are expired, and then reformat/erase
non-deduplicated cartridges which have no or few dependent cartridges. When
reformatted/erasing non-deduplicated cartridges, the disk space is only freed up if dependent
cartridges are also reformatted/erased.
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
Application
Guidelines.
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. The deduplication limit per node varies depending on the node
type, the backup application type, the data type, and whether the device is acting as a
replication source. Also, any replication data being sent to this device also requires additional
node performance.
94
Accelerated Deduplication
VLS Configuration and Backup
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