How to change default location and the number of configuration copies saved in /etc/vx/cbr/bk/ for all VRTSvxvm releases after 5.x ?

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Article ID: 100020480

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Cause

1. The number of configuration copies saved in /etc/vx/cbr/bk/ directory now defaults to only one in for version of VRTSvxvm 5.x and  greater as compared to previous versions where the default was to save 5 copies of each diskgroup private region configuration.

2. Versions  of VRTSvxvm 5.x and greater allows for larger default private region and and as a result may require large amount of space on the / (root) filessystem. The default directory for the configuration database is located in  /etc/vx/cb/bk  and may cause space issues.

 

Resolution

Option 1: Change the number of configuration copies saved in /etc/vx/cbr/bk/
 
The disadvantage of having one copy only is that if there is any issue or an incore corruption in the vxconfigd kernel configuration then the corruption is mitigated to the backups and hence defeating the entire purpose of the configuration backups in /etc/vx/cbr/bk/ directory.

The space requirement for each configuration copy of a diskgroup has increased due to the increase in the size of the Private Region (32Mb) on disks in Volume Manager and will have to be considered.

It will be safe to reserve twice the required disk space for the diskgroup configuration which gets saved in the / (root)  filesystem.For example
{32 MB X (Number of Disk Groups) X (Number of Copies)} x 2  = 6400Mb for  20 disk groups with 5 configuration copies.

To increase the default number of configuration copies = 1 to 5 for example, we need to update the /etc/vx/cbr/bk_config file as follows:

# echo "NUM_BK=5" >> /etc/vx/cbr/bk_config
 
Option 2: Change the default location=/etc/vx/cbr/bk/ of configuration copies to a new location
 
If the increase in number of configuration as shown above causes a space restriction  in the / (root) filesystem. Change the location to your preferred new location but it is very important  the directory structure /etc/vx/cbr  and any config files(e.g. bk_config) are NOT deleted

To change the default location for the configuration database , you need update the  /etc/vx/cbr/bk_config file as follows:
 
# echo "CF_BKUP_PATH=/" >> /etc/vx/cbr/bk_config

Example: Make sure the new directory exist
 
# echo "CF_BKUP_PATH=/my_backup/new_loc" >> /etc/vx/cbr/bk_config

For  either one or both options above to take effect,  the "vxconfigdbackupd" daemon has to be restarted manually or the change will take effect on the next reboot:
To restart vxconfigbackupd

# ps -ef | grep vxconfig
   root 14297        1   0   Mar 02 ?             0:22 vxconfigd -x syslog -m boot
   root 17900 17759   0 17:03:33 pts/3       0:00 /sbin/sh - /usr/lib/vxvm/bin/vxconfigbackupd
   root 17759 28896   0 17:03:32 pts/3       0:00 /sbin/sh - /usr/lib/vxvm/bin/vxconfigbackupd

# kill -9 17900
# kill -9 28896

# ps -ef | grep vxconfig
   root 14297       1   0   Mar 02 ?             0:22 vxconfigd -x syslog -m boot

# /usr/lib/vxvm/bin/vxconfigbackupd &

# ps -ef | grep vxconfig
   root 14297        1   0   Mar 02 ?             0:22 vxconfigd -x syslog -m boot
   root 18497 18356   0 17:05:26 pts/3       0:00 /sbin/sh - /usr/lib/vxvm/bin/vxconfigbackupd
   root 18356 28896   0 17:05:25 pts/3       0:00 /sbin/sh - /usr/lib/vxvm/bin/vxconfigbackupd

Depending on which options where implemented the results are as follows:

Option 1 only:  vxconfigbackupd will now backup up to 5 configuration copies in the /etc/vx/cbr/bk/  directory for each diskgroup in the system.
Option 2 only:  vxconfigbackupd will now backup up to 1 configuration copies in the /my_backup/new_loc  directory for each diskgroup in the system
Option 1  & 2:   vxconfigbackupd will now backup up to 5 configuration copies in the /my_backup/new_loc  directory for each diskgroup in the system 


Applies To

All platforms and VRTSvxvm verisions 5.x and greater

Issue/Introduction

1. How to change the number of configuration copy to allow access to more  than 1 set of configuration files

2. How to changethe default location = /etc/vx/cbr/bk for the configuration database to prevent / (root) filesystem becoming full
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