Key performance considerations for NetBackup 7.6 master servers


The issues that improve the performance of NetBackup relational database on the master server are outlined in this article.

Error Message

Status Code: 252 Cannot Connect to Database

Slow Catalog backup

Sluggish or hung NetBackup job throughput


The following are the key factors for reviewing the NetBackup master system health.

NetBackup Fixes:

Thread optimization with limiting MAX_QUERY_TASKS is addressed in

Additional System Configurations for improved performance:

Disk I/O

Disk performance will have a significant impact on the performance of the NetBackup master.  It is required that the average service times for disks NetBackup resides remain lower than 20ms.  The following article is a outlines the underlying disk options and requirements:

Disk Layout

If disk performance is non-optimal it may be beneficial to move components of NetBackup to different disks to remove I/O contention.  The following article outlines the disk layout options for improved performance:

Semaphore Usage (Unix Masters)

With many process running on the master, it is important to review system semaphore usage and potentially raise the semaphore limits to ensure no semaphore constraints.  The following are recommended values:

Recommended sem values:
300     307200    32    1024

More information on configuring these values can be found in the following article:

File Descriptors (Unix Masters)

If the operating system doesn't have enough file descriptors configured, performance will be negatively impacted.  File descriptors should be set to a minimum of 8000 and monitored to ensure that value is sufficient on high performing systems.  More information on this recommendation can be found here:

Sybase Threads

7.6 contains an updated Sybase version that performs thread optimization as required. Customers should no longer set -gn manually in NetBackup 7.6 and higher.

Database Memory Allocation

NetBackup 7.6 auto allocates 30% of the system memory up to 32GB on install.  Customers should not adjust the -ch value in NetBackup 7.6 and higher.

Oracle Backup Format

NetBackup 7.6 includes improvements for Oracle image generation and validation.  Customers are encouraged to follow the best practices for Oracle images but the database performance hit is not as detrimental in NetBackup 7.6 and higher.


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