cluster lock

[newunix]

what is the use of cluster lock disk(can any one please explain in simple terms ) and how to set the cluster lock

[Mel Burslan]

cluster lock is a tie-breaking mechanism, mandatory for clusters with size of 3 servers or less, optional for more than 3 servers big clusters.

Its purpose is, let's say, TCP-IP network equipment died, or one server's NIC bummed out. And for simplicity, lets assume you only have 2 nodes in the cluster.

Both servers are up and both think that the other one has died. So, they decide to form a single server cluster. Since both of them see the same storage, if both form that cluster, they may corrupt data.

So, the cluster lock, or as it is widely known as cluster lock disks, come into action as a tie breaker. These disks are devices such that, only one of the cluster members can get a lock on them (hence the name lock). Which ever server locks this disk for its own use, forms the cluster. Other servers, who can not lock it, will say, okay, the cluster is formed somewhere else, so I am going to shut myself down and wait for help and induce a TOC (effectively shutdown -h)

Simple enough ??

[melvyn burnard]

Take a read of this document, it should explain it all
http://bizsupport2.austin.hp.com/bc/docs/support/SupportManual/c02056095/c02056095.pdf