topic Re: 3 node cluster using EMC, lock disk issue in Operating System - HP-UX

3 node cluster using EMC, lock disk issue

Andrew R. — Mon, 11 Mar 2002 15:20:59 GMT

I have 3 node A,B,C . A and C are the primary nodes and B is the adobtive node for both primary's. The three servers are connected to EMC frame. I tried to use GateKeeper (2MB) disk which is only shared disk between the servers but I'm getting some errors on server B:
vmunix: LVM: vg[6]: pvnum=0 (dev_t=0x1f0bf000) is POWERFAILED
vmunix: Error writing VGDA [1] to disk H/W path ..... (error = 5)

This happen when I try to actvivate or display the VG on server 'B' note, the export/import works fine.Also note, on the other 2 servers 'A' and 'C' it's Ok.
Now, I'm thinking to remove the lock disk at all since it is a 3 node and the lock disk is not important in this case. What do you think ?

Re: 3 node cluster using EMC, lock disk issue

melvyn burnard — Mon, 11 Mar 2002 15:31:56 GMT

Are you saying you are trying to use the GateKeeper device as a lock disc?

If so, this does not work and is unsupported.

Off the record, there is no official figure released, but in testing I have found that anything less than 20Mb does not work anyway, and as the GK is only 2Mb............

Re: 3 node cluster using EMC, lock disk issue

Sanjay_6 — Mon, 11 Mar 2002 15:42:19 GMT

Hi Andrew,

You should be using a disk from the EMC as the lock disk. The gatekeeper device is to access the EMC disk and is not supposed to be used as lock device.

Hope this helps.

Regds

Re: 3 node cluster using EMC, lock disk issue

Andrew R. — Mon, 11 Mar 2002 21:07:51 GMT

Thanks for the reply,

The problem is that the PRIM nodes are using two different applications,so in order to share the same VG I have to add the same set of disks to one more server (either from CtoA or from AtoC) In both cases the disks under either VG's are a lot, 10 disks under each).

Now,I can apply the cluster without using lock disk. What is the disadvantage and what do you recommend.

thanks again

Re: 3 node cluster using EMC, lock disk issue

Jeff Schussele — Mon, 11 Mar 2002 21:43:05 GMT

Andrew,

With a 2 (primary) node cluster you HAVE to use a lock disk to break the tie. Sorry, you have no choice.

With a 3 node cluster it's not required - and not recommended for 4 & up.

You'll have to bite the bullet & designate a LUN for the lock disk.

Rgds,
Jeff