Backups fail intermittently with status 89 if insufficient shared memory identifiers are available

Article:TECH75597  |  Created: 2009-01-14  |  Updated: 2012-06-02  |  Article URL http://www.symantec.com/docs/TECH75597
Article Type
Technical Solution


Environment

Issue



Backups fail intermittently with status 89 if insufficient shared memory identifiers are available


Error



The bptm or bpdm debug log will display an entry similar to the following if the number of shared memory identifiers OR  shared memory space has been exceeded.

<16> create_shared_memory: could not allocate enough shared memory for backup buffers, No space left on device

 


Cause



The NetBackup Tape Manager (bptm) or Disk Manager (bpdm) will fail a backup or restore with status 89:
  -  If there is an insufficient number of shared memory identifiers available.  
  -  If there is insufficient shard memory available.
When if either resource is exhausted, the next shmget system call will return errno 28 (ENOSPC) and the media manager will fail the job.

 

Solution



Troubleshooting:

The number of allocated shared memory segments can be monitored over time using various tools to confirm the number of identifiers used, e.g.

echo "`date` : ALL Active memory segments = `ipcs -m -A | wc -l`"

Note the back-quotes around the embedded commands.  If using Solaris 10 projects, the subset of segments utilized by NetBackup can be monitored separately, e.g.

echo "`date` : Active NBU memory segments = `ipcs -m -A | grep 'NetBackup' | wc -l`"

A periodic review of the output can be used to determine if the actual use is approaching the configured limits,

Resolution:

Modify the kernel or project configuration to increase the number of shared memory identifiers available for use by NetBackup and/or other co-resident applications.  
See the related documents section for details.
 

For Solaris10 NetBackup project:
  List the current configuration.
  # projects -l NetBackup
 
If  'project.max-shm-ids'  is not listed in the output, add it using "projmod -a"  with the following line--
    # /usr/sbin/projmod -a -K 'project.max-shm-ids=(privileged,2048,deny)' NetBackup
If  'project.max-shm-ids'  is listed in the output,  swap the current  value using "projmod -s" with the following line--
    # /usr/sbin/projmod -s -K 'project.max-shm-ids=(privileged,2048,deny)' NetBackup
Then verify the change with      
    # projects -l NetBackup
 
No reboot required

--------------------------------------------------- 

For Solaris10 using   /etc/system   file for the NBU resources:
Edit the file and add or change the following line:

set shmsys:shminfo_shmmni=2048                 *Solaris10 default =128

 Reboot required to pick up the file changes
 




Legacy ID



335338


Article URL http://www.symantec.com/docs/TECH75597


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