nbmemoblocks

nbmemoblocks [-id block_id] [-r block_id]

-id block_id
    Displays detailed information for a specific NetBackup shared memory block identified by its unique block_id. If omitted, the command lists all active NetBackup shared memory blocks.

-r block_id
    (Caution: Use with extreme care!) Attempts to release (detach and remove) a specific NetBackup shared memory block identified by its block_id. Improper use of this option can lead to NetBackup process instability, crashes, or data corruption. It should only be used under direct guidance from Veritas Support.

nbmemoblocks is a specialized diagnostic utility bundled with Veritas NetBackup. Its primary function is to display information about shared memory segments, often referred to as "memo blocks," that are currently in use by various NetBackup processes and daemons.

This command is invaluable for NetBackup administrators and support personnel who need to troubleshoot performance issues, memory leaks, or understand resource utilization within a NetBackup environment. The output typically includes details such as the unique ID of each shared memory block, its size in bytes, and the number of NetBackup processes currently attached to it. By providing insight into the shared memory landscape, nbmemoblocks helps in diagnosing issues where NetBackup processes might be consuming excessive memory or or failing to release shared resources properly. It is a critical tool for maintaining the stability and efficiency of NetBackup operations.

nbmemoblocks is specific to the Veritas NetBackup software suite and will not function outside of a NetBackup installation. The -r (release) option is highly destructive and should only be used by experienced administrators under explicit guidance from Veritas technical support, as it can cause severe disruption to NetBackup operations. The command only displays shared memory segments managed or utilized by NetBackup processes, not all shared memory on the system. The output format and available options might subtly change across different versions of NetBackup.

This command is primarily a diagnostic tool intended for use by NetBackup administrators, database administrators, and Veritas support personnel to analyze and troubleshoot memory-related issues within the NetBackup environment. It is not a general-purpose Linux utility.

When run without arguments, nbmemoblocks typically provides a columnar output listing shared memory segments. Key columns usually include:

• ID: The unique identifier for the shared memory segment.
• SIZE: The allocated size of the memory block in bytes.
• ATTACH: The number of NetBackup processes currently attached to this block.

Executing nbmemoblocks and obtaining complete information, especially related to shared memory segments, typically requires root or equivalent administrator privileges on the system where NetBackup is installed.

nbmemoblocks has been an integral diagnostic component of the Veritas (formerly Symantec) NetBackup software suite for many years, dating back to its earlier versions. It was developed to provide administrators with a low-level view into the shared memory resources used by NetBackup's complex multi-process architecture, aiding in troubleshooting and performance tuning specific to the product's internal operations. Its design reflects the need for specialized tools to manage and monitor proprietary system components.

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