Symantec NETBACKUP 7 - Manual (Page 54)

Table 5-3 Deduplication storage unit properties (continued)
Description Property
The Maximum concurrent jobs setting specifies the maximum number
of jobs that NetBackup can send to a disk storage unit at one time.
(Default: one job. The job count can range from 0 to 256.) This setting
corresponds to the Maximum concurrent write drives setting for a
Media Manager storage unit.
NetBackup queues jobs until the storage unit is available. If three
backup jobs are scheduled and Maximum concurrent jobs is set to
two, NetBackup starts the first two jobs and queues the third job. If a
job contains multiple copies, each copy applies toward the Maximum
concurrent jobs count.
Maximum concurrent jobs controls the traffic for backup and
duplication jobs but not restore jobs. The count applies to all servers
in the storage unit, not per server. If you select multiple media servers
in the storage unit and 1 for Maximum concurrent jobs, only one job
runs at a time.
The number to enter depends on the available disk space and the
server's ability to run multiple backup processes.
Warning: A Maximum concurrent jobs setting of 0 disables the storage
unit.
Maximum
concurrent jobs
Deduplication storage unit recommendations
You can use storage unit properties to control how NetBackup performs.
Increase the Maximum concurrent jobs gradually
Symantec recommends that you increase the Maximum concurrent jobs value
gradually. The initial backup jobs (also known as initial seeding) require more
CPU and memory than successive jobs. After initial seeding, the storage server
can process more jobs concurrently. Gradually increase the jobs value over time.
Testing shows that the upper limit for a storage server with 8GB of memory and
4GB of swap space is 50 concurrent jobs.
Configure a client-to-server ratio
For a favorable client-to-server ratio, you can use one disk pool and configure
multiple storage units to separate your backup traffic. Because all storage units
use the same disk pool, you do not have to partition the storage.
Configuring deduplication
Configuring a deduplication storage unit 54