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Configuration copies disabled

Hi,

I executed the command "vxdg list dg" and saw that the configuration copies on most of the disks were in "disabled" state. Only 5 disks had the copies in enabled state except 20. Is this right? Shouln't the copies on all disks be in enabled state?

 

Thanks,

1 Solution

Accepted Solutions
Accepted Solution!

you can also provide the

you can also provide the nconfig value at the time of initiating the diskgroup ...

Point to note is, when a diskgroup is imported, all the config copies are compared & if they all are identical then diskgroup is imported... if they differ then diskgroup import may fail..

If you put config on all the disks, you are safe at one side that if something goes wrong, config copies are available on all the disks to recover diskgroup, however on other side, diskgroup import may take little more time as it will scan more number of disks... this will keep growing if more disks are added in diskgroup...

Also, interesting to read the article from vxvm admin guide:

 

Number of configuration copies for a disk group


Selection of the number of configuration copies for a disk group is based on a trade-off between redundancy and performance. As a general rule, reducing the number of configuration copies in a disk group speeds up initial access of the disk group, initial startup of the vxconfigd daemon, and transactions that are performed within the disk group. However, reducing the number of configuration copies also increases the risk of complete loss of the configuration database, which results in the loss of all objects in the database and of all data in the disk group.


The default policy for configuration copies in the disk group is to allocate a configuration copy for each controller identified in the disk group, or for each target that contains multiple addressable disks. This provides a sufficient degree of redundancy, but can lead to a large number of configuration copies under some circumstances. If this is the case, we recommended that you limit the number of configuration copies to a maximum of 4. Distribute the copies across separate controllers or targets to enhance the effectiveness of this redundancy. To set the number of configuration copies for a new disk group, use the nconfig operand with the vxdg init command.

See the vxdg(1M) manual page for details.

You can also change the number of copies for an existing group by using the vxedit set command. For example, to configure five configuration copies for the disk group, bigdg, use the following command:

# vxedit set nconfig=5 bigdg

See the vxedit(1M) manual page.

 

so nothing wrong, thats default to keep diskgroup config copies on few disks..

 

Gaurav

View solution in original post

3 Replies

Hi,   Yes, that is the

Hi,

 

Yes, that is the default setting. It does not place configuration copies in all the disks and that's fine what you have observed. It is not required to have all the disks to have configuration copies as it is very unlikely that all the disks would physically crash at the same time.

 

If you still wish to have all the disks to have configuration copies then you can run the following command:

vxedit set nconfig=<numberic value> <disk group name>

 

Regards,

Dev

Accepted Solution!

you can also provide the

you can also provide the nconfig value at the time of initiating the diskgroup ...

Point to note is, when a diskgroup is imported, all the config copies are compared & if they all are identical then diskgroup is imported... if they differ then diskgroup import may fail..

If you put config on all the disks, you are safe at one side that if something goes wrong, config copies are available on all the disks to recover diskgroup, however on other side, diskgroup import may take little more time as it will scan more number of disks... this will keep growing if more disks are added in diskgroup...

Also, interesting to read the article from vxvm admin guide:

 

Number of configuration copies for a disk group


Selection of the number of configuration copies for a disk group is based on a trade-off between redundancy and performance. As a general rule, reducing the number of configuration copies in a disk group speeds up initial access of the disk group, initial startup of the vxconfigd daemon, and transactions that are performed within the disk group. However, reducing the number of configuration copies also increases the risk of complete loss of the configuration database, which results in the loss of all objects in the database and of all data in the disk group.


The default policy for configuration copies in the disk group is to allocate a configuration copy for each controller identified in the disk group, or for each target that contains multiple addressable disks. This provides a sufficient degree of redundancy, but can lead to a large number of configuration copies under some circumstances. If this is the case, we recommended that you limit the number of configuration copies to a maximum of 4. Distribute the copies across separate controllers or targets to enhance the effectiveness of this redundancy. To set the number of configuration copies for a new disk group, use the nconfig operand with the vxdg init command.

See the vxdg(1M) manual page for details.

You can also change the number of copies for an existing group by using the vxedit set command. For example, to configure five configuration copies for the disk group, bigdg, use the following command:

# vxedit set nconfig=5 bigdg

See the vxedit(1M) manual page.

 

so nothing wrong, thats default to keep diskgroup config copies on few disks..

 

Gaurav

View solution in original post

Thanks Gaurav and Dev

Thanks Gaurav and Dev