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NetBackup System Administrator’s Guide - Windows NT Server
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However, when you use multiplexing, expect reduced performance on restores
due to the extra time spent reading the images.
Note:
To reduce the impact of multiplexing on restore times, set maximum
fragment size for the storage units to a value other than zero.
How to Configure Multiplexing
Multiplexing must be set in two places in the NetBackup configuration:
• Storage unit
• Schedule
Note:
If you change these values, it does not take effect until the next time a
schedule runs.
Maximum Multiplexing Per Drive for Storage Unit
The Maximum Multiplexing per drive property for a storage unit specifies how
many backups NetBackup can multiplex onto any single drive in the storage
unit. You set this value for each storage unit (see Chapter 2, “Managing Storage
Units”). The number can range from 1 through 32, where 1 is the default and
specifies no multiplexing.
Choose a value based on the ability of your CPU to handle parallel jobs.
Because extra buffers are required, memory is also important. If the server
cannot perform other tasks or runs out of memory or processes, reduce the
Maximum Multiplexing setting for the storage unit. Consider the following
when estimating the load that multiplexing can potentially put on your CPU:
• The maximum number of concurrent-backup jobs that NetBackup is
allowed to attempt, equals the sum of the concurrent-backup jobs that can
run on the storage units.
• The maximum number of concurrent-backup jobs that can run on a single
storage unit equals:
Maximum Multiplexing per drive x number of drives
NetBackup 3.2 System Administrator's Guide for Windows NT
NetBackup 3.2 System Administrator's Guide for Windows NT