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  1. Home
  2. NetBackup™ Backup Planning and Performance Tuning Guide
  3. Tuning the NetBackup data transfer path
  4. NetBackup network performance in the data transfer path
  5. Setting the NetBackup client communications buffer size
NetBackup™ Backup Planning and Performance Tuning Guide

Setting the NetBackup client communications buffer size

The NetBackup client has a tunable parameter to adjust the size of the network communications buffer. This buffer writes data to the network for backups.

This client parameter is the counterpart to the network buffer size parameter on the media server. The network buffer sizes are not required to be the same on all of your NetBackup systems for NetBackup to function properly. However, if the media server's network buffer size is the same as the client's communications buffer size, you may achieve better performance.

To set the communications buffer size parameter on Linux/UNIX clients

  • Create the /usr/openv/netbackup/NET_BUFFER_SZ file.

    As with the media server, the file should contain a single integer that specifies the communications buffer size. Generally, performance is better when the value in the NET_BUFFER_SZ file on the client matches the value in the NET_BUFFER_SZ file on the media server. The value in each file must be within the value range that operating system allows. Otherwise, the established connection may behave erratically. More information about the buffer files is available:

    Best practices for NET_BUFFER_SZ and Buffer_size

    The NET_BUFFER_SZ_REST file is not used on the client. The value in the NET_BUFFER_SZ file is used for both backups and restores.

To set the communications buffer size parameter on Windows clients

  1. From Host Properties in the NetBackup Administration Console, do the following: expand Clients and open the Client Properties > Windows Client > Client Settings dialog for the client on which the parameter is to be changed.
  2. Enter the new value in the Communications buffer field.

    This parameter is specified in number of kilobytes. The default value is 128. However, for the best performance, set the value to 0 to allow the operating system to choose the buffer size.

    Because local backup jobs on the media server do not send data over the network, this parameter has no effect on these local operations. Only the NetBackup bpbkar32 process uses this parameter. It is not used by any other NetBackup processes on a primary server, media server, or client.

  3. If you modify the NetBackup buffer settings, test the performance of restores with the new settings.

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