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Cluster swap to larger nodes

GlenRB
Advisor

Cluster swap to larger nodes

I don't think this will be a problem, but I'd like to verify.

 

I need to replace a set of older 4200 G1 3.5TB nodes that are full.  I would like to do a cluster swap and replace those two nodes with two 7TB 4330s.  I'm assuming and hoping this won't be a problem since both old nodes are going out and being swapped with two larger nodes.

 

Has anyone done this and can verify this isn't a problem?

 

Thanks.

4 REPLIES
GlenRB
Advisor

Re: Cluster swap to larger nodes

It would be nice if someone from HP even occassionally responded to questions in this forum.  So it looks like I'll find the answer to this on my own tomorrow.

 

My guess is that this won't be a problem but now I'm thinking I won't be able to add the new nodes v12.5 to the existing management group running 9.5.

 

Any chance anyone has an answer as the whether or not that is possible?

giladzzz
Honored Contributor

Re: Cluster swap to larger nodes

hi

I think you can not add 12.5 nodes to a 9.5 cluster

but you can create a new cluster under the same managment group

and use peer motion to move the lunes ( you just edit a lun and choose

the new cluster) this can be done with out downtime just make sure

your hosts recognises the new cluster virtual IP before you start.

Regards

 

oikjn
Honored Contributor

Re: Cluster swap to larger nodes

not sure about the 9.5 vs 12.5 issue, but the answer regarding the size question is a definite YES.  If you do an exchange, you can exchange nodes of different sizes and as long as the size is larger, you will be able to complete it without a problem and when you exchage all the nodes out you will get full access to the complete new node size.

 

I have done this and can verify it does "work".  I put that in quotes as I ran into a problem with cluster utilization that caused me to lose LUN access during the exchange because of a bug in the way it reports usable space.  I believe about 48 hours after I did this, HP independently came out with a patch to fix something that sounded almost exactly like the problem I faced.   Make sure you are fully patch as best you can before you make the exchange or just do what the other poster suggested which is create a new cluster and move the LUNs to the new cluster, but that will require reconfiguration of the initiators on each server (which sometimes is a good thing and other times is just too much of a pain in the a$$).

GlenRB
Advisor

Re: Cluster swap to larger nodes

I can answer a few of these question since I worked through this today.

 

The following is true without enlisting the help of support:

 

You cannot add a 12.0 node to a 9.5 management group.  It will not let you.  So while you could create a new cluster, you could not add the 12.0 nodes to that cluster either because you cannot get the nodes into the management group.

 

You could make a new management group but I didn't want to go that route.

 

But, you can have support start the CMC in support mode and then you can force the nodes into the 9.5 management group.  Once that is done you can start the cluster swap.  I then had 4 nodes in the MG so ran managers on two new nodes and one of the old nodes and remove the 9.5 FOM.  Once the restripe is done, I will remove the two old nodes and put in a new 12.5 FOM.

 

As for the size, yes, it does appear to be reporting the new increased size.