NetBackup Network Performance

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NetBackup Client Performance

This section lists some factors to consider when you evaluate the NetBackup client component of the NetBackup data transfer path. Examine these conditions to identify possible changes that may improve the overall performance of NetBackup.

  • Disk Fragmentation. Fragmentation is a condition where data is scattered around the disk in non-contiguous blocks. This condition severely impacts the data transfer rate from the disk. Fragmentation can be repaired using hard disk management utility software offered by a variety of vendors.

  • Virus Scanning. If virus scanning is turned on for the system, it may severely impact the performance of the NetBackup client during a backup or restore operation. This may be especially true for systems such as large NT file servers. You may wish to disable virus scanning during backup or restore operations to avoid the impact on performance.

  • NetBackup Notify Scripts. The bpstart_notify.bat and bpend_notify.bat scripts are very useful in certain situations, such as shutting down a running application to back up its data. However, these scripts must be written with care to avoid any unnecessary lengthy delays at the start or end of the backup job. If the scripts are not performing tasks essential to the backup operation, you may want to remove them.

  • NetBackup Software Location. If the data being backed up is located on the same physical disk drive as the NetBackup installation, performance may be adversely affected, especially if NetBackup debug log files are being used. If they are being used, the extent of the degradation will be greatly influenced by the NetBackup verbose setting for the debug logs. If possible, install NetBackup on a separate physical disk drive to avoid this disk drive contention.

  • Open Transaction Manager (OTM). When OTM is enabled, there is a delay at the start of the backup while information is gathered about the volumes being snapped and while the OTM driver is waiting for the disk activity to quiesce. In some cases, there will be an additional delay while OTM creates the snapshot cache file. NetBackup transfer rates are affected by this delay because NetBackup treats the start of the data transfer as the time that the backup process is started on the client. You may wish to disable OTM to eliminate this delay unless it is needed to back up open files.

  • Job Tracker. If the NetBackup Client Job Tracker is running on the client, then NetBackup will gather an estimate of the data to be backed up prior to the start of a backup job. Gathering this estimate will affect the startup time, and therefore the data throughput rate, because no data is being written to the NetBackup server during this estimation phase. You may wish to avoid running the NetBackup Client Job Tracker to avoid this delay.

  • Client Location. You may wish to consider adding a locally attached tape device to the client and changing the client to a NetBackup media server if you have a substantial amount of data on the client. For example, backing up 100 GBs of data to a locally attached tape drive will generally be more efficient than backing up the same amount of data across a network connection to a NetBackup server. Of course, there are many variables to consider, such as the bandwidth available on the network, that will affect the decision to back up the data to a locally attached tape drive as opposed to moving the data across the network.

  • Determining the Theoretical Performance of the NetBackup Client Software. There is a useful feature in the NetBackup client software utility bpbkar32 that may be used to determine the speed at which the NetBackup client can read the data to be backed up from the disk drive. This feature can be used to eliminate as a possible performance bottleneck the speed at which the data can be read when you are attempting to improve a poorly performing NetBackup installation. Use the following syntax for this utility:

     bpbkar32 -nocont <filepath> > NUL 2 > NUL 

    In the above syntax, <filepath> would be replaced with the path to the data to be read from the disk, C:\ for example. Using this syntax simulates an infinitely fast speed for the other components of the NetBackup data transfer path, such as the network.

    You can view the performance statistics of the operation in the bpbkar debug log file, or use a stopwatch to time the operation and then manually calculate the performance statistics.



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Implementing Backup and Recovery(c) The Readiness Guide for the Enterprise
Implementing Backup and Recovery: The Readiness Guide for the Enterprise
ISBN: 0471227145
EAN: 2147483647
Year: 2005
Pages: 176

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