Configuration Performance factors
The default value for the NUMBER OF BUFFERS PER STRIPE is 2, which allows double buffering. You may get slightly better performance by increasing this vaule to a higher value. In the MS SQL Client interface, you can change this value through the NetBackup client properties dialog box. (File > Set NetBackup client properties). Otherwise, you can use the BUFFERS parameter to set this value when you create a batch file manually.
See “Overview of batch files” on page 105.
You can divide your backup operation into multiple concurrent streams in any situation in which SQL Server dumps data faster than your tape drive is capable of writing. Although NetBackup supports multiplexing many stripes to the same drive, you generally will realize performance gains only if you use the same number of tape drives as streams.
To divide a backup operation into multiple stripes, modify the Stripes value. This value is in the Backup Microsoft SQL Server objects dialog box of the MS SQL Client interface.
Shared memory usage
If NetBackup Server is installed on the same host as NetBackup for SQL Server, then you will obtain optimal performance by using shared memory for data transfer instead of sockets. Shared memory is the default for this configuration and will be used unless you create a install_path\NetBackup\NOSHM file.
Alternate buffer method
NetBackup for SQL Server supports an alternate buffer method which optimizes CPU usage by allowing NetBackup and SQL Server to share the same memory buffers without transferring data between them.
The alternate buffer method for backup and restore typically does not improve data transfer rate, only CPU utilization. A situation may occur in which the transfer rate is significantly degraded when alternate buffer method is in use. To improve the transfer rate set the MAXTRANSFERSIZE for the backup to the maximum allowed, which is 4 megabytes. Set this parameter by choosing File > Set NetBackup client properties or add this parameter to a batch file. See “Overview of batch files” on page 105.
Alternate buffer method with backup operations This method is chosen automatically for backups if all of the following conditions apply: