Plex mirroring in vxvm

[Srikanth Arunachalam]

Hi,

I understand that software mirroring can be done by making use of vxassist or vxmake command. In case of vxassist, although I may create mirroring..the plex name and sub-disk names get system defined names.
In case of vxmake we can specify our own name for it. The following are the question I have.

(1) vxmake is plex level mirroring, will vxassist based mirroring also do the same thing on system defined plex names ?

(2) In case of vxmake,I specify both the names of plex associated to the volume at the same time. How do I ensure that which of this is primary source and which is mirrored one.

(3) In case of disk failure in such mirrored disk, how do I break mirror and create volumes on the survived plex alone.

Thanks,
Srikanth

[Mridul Shrivastava]

1. If a volume contains more than one plex of same size they are mirrored one only. plex is the term used for mirroring. It hardly matters you are using vxassist or creating manually.
2. There is nothing like primary or secondary source as it writes data on both plexes and if any one fails it will keep on updating data on the good one.
3.Once you confirm the failed disk, plex to which disk belongs can be removed without affecting the good one.

For more details about vxvm please follow the below link:

http://docs.hp.com/en/B7961-90025/index.html

[Albert_31]

1) with regards to mirroring, no matter which command used, the method of mirroring is the same, with each command you get more /less features or options..etc.

2) There is no funda as primary and secondary copy.. you can do one thing is to specify the primary disk first and the secondary disk next...in vxvm the write policy is parallel and you have no control on it...dont compare pv1 and pv2 as specified in LVM.

3) I didnt quite understand what you wanted here.. but here is the answer
if a disk has failed, then the plex which has it subdisk on the failed disk is disabled, the volume is still enabled since the other plex is healthy. You have to use the vxassist command to remove the plex..if you want to..it does not affect the volume at all

Just for your information

a) Volumes are made up of plexes and plexes are made up of subdisk.

b) If there are more than one plex in a volume, the plexes are mirror copies of each other.

regards

Albert