lock vg or lock disk

[rayche]

Hi,

When I configure cluster, I just need define lock disk or should define lock vg at the same time ?
If I define the second lock disk, that mean when the first one failed, cluster will not be affected, because we have the second lock disk, right ?

Thanks.

[Rajeev Shukla]

Yes when you define or create a cluster you need to assign a lock disk which is seen by all the nodes in the cluster and a cluster lock VG seen from all nodes in the cluster.
I haven't come accross defining more than one cluster lock disk in a cluster and reason i back is purely say if the cluster lock disk doesn't fail but the path to that disk fails from one node in the cluster, in that case that node will try to lock the other cluster lock disk where as other nodes will still use the previous disk making the cluster unstable.

[rayche]

Hi Rajeev Shukla,

So it is better we do not use 2 lock disk,right ? but,when the lock disk failed suddenly, how can cluster do ?

Another question, we must use lock VG,not just define lock disk, right ? could u tell me the reason ?

Thanks.

[Rajeev Shukla]

You must define both the cluster lock VG and cluster lock disk. And yes if the cluster lock disk fails then the running cluster is not affected, cluster lock disk is queried only in the event of change in the number of nodes in the cluster, like node joining or leaving. Now if the cluster lock disk fails then it is required to quickly modify the cluster config file with a new disk and reapply the config file to the cluster.

[rayche]

Rajeev Shukla ,

Thanks for your help first.

Yes,I can change configuration and apply it, but I think the action cannot be finished when the whole cluster is online,right ? Our system is production system, we cannot shutdown cluster, how can I do ?

thanks.