about vglock

[Muhammad Shamroze]

I want to know what is the term vglock means?

thanks

[Devender Khatana · Accepted solution]

Hi,

A vg used as cluster lock is generally called vglock. cluster lock refer to a tie breaker short of thing which is generally used in a two node service guard cluster. In the event of failure of communication between two nodes whoever takes control of lock first will continue to run cluster and other node will be halted.

Hence the purpose of this is to ensure both nodes independently form two seperate clusters in the even of failure of communication among them.

HTH,
Devender

[Arunvijai_4]

Hello,

vglock is used in service guard 2-node clusters.

http://forums1.itrc.hp.com/service/forums/questionanswer.do?threadId=700211
http://forums1.itrc.hp.com/service/forums/questionanswer.do?threadId=724058

-Arun

[Steven E. Protter]

Shalom Muhammad,

As noted vglock of for MC/Serviceguard clusters.

Cluster locking is a mechanism by which a cluster stays healthy. It is useful for two node clustsrs alone.

For three or above nodes you need a lock manager server, which can be Linux or HP-UX, running some free software.

What happens with a cluster lock disk is that if a cluster loses heartbeat communications, the two nodes attempt to lock the cluster lock disk. Whichever node gets this done first continues to function.

The other node does a TOC, transfer of control which is similar to a system crash. It reboots. It will rejoin the cluster if the problem that disrupted heartbeat is fixed. If not it will remain outside the cluster waiting for someone to fix the problem with heartbeat.

SEP