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Physically moving Multi-site Cluster to Single site

JKersey
Occasional Contributor

Physically moving Multi-site Cluster to Single site

Do to budget cuts I'm having to move a four node P4000 (DL320's running SAN/iQ v8.5) Multi-site cluster and Virtual Manager to a single site.  At the single site the Multi-site cluster will still be setup across mutliple subnet's to continue to be a Multi-site cluster in the event management decides to fund a second site in the future.  

 

The questions I have is can I power down only the two nodes I'm moving or should I power down everything?  I'm thinking if I move the Virtual Mgr to one of the nodes not being shutdown I should be able to keep the cluster up. 

 

Has anyone does this type of migration before?

 

 

 

5 REPLIES
oikjn
Honored Contributor

Re: Physically moving Multi-site Cluster to Single site

as long as you configured your system correctly and you have quorum setup correct, there should be no issue with powering down the second site and moving it while the other is up.  IF you only have NR10, then you will lose your redundancy during the move which means you either need to migrate your LUNs to NR10+1, shutdown the entire cluster, or just take the risk that there will not be a problem during the move.

 

I would suggest the NR10+1 option if you have the space.

MichaelGruber
Occasional Contributor

Re: Physically moving Multi-site Cluster to Single site

Hello all,

I would like to do the reverse of this.  We have a single site cluster that I would like to move 1 node offsite.  What is the best way to accomplish this without losing connectivity to the data as this is in production.

oikjn
Honored Contributor

Re: Physically moving Multi-site Cluster to Single site

while still on-site, just go into CMC, select the node and edit the site settings to put it at a different site.  You will likely need a FOM at a 3rd site and you have to think about issues of split-brain when dealing with multi-sites.  99% of the time doing multi-site is NOT the best solution for you even though it sounds like a great idea and the feature is "free"  the required bandwidth and latency make it $$$$ and typically not worth it for most places.

 

once you change the logical site definitions on the nodes, the cluster will switch to multi-site mode and restripe to ensure that the stripe goes between the two sites.  Then just make sure the initiator servers are assigned to the correct sites.  Finally you can then move the node you want to the new physical location and then change its IP after its moved using the console. 

If you only have two nodes and want to move one offsite, I would think twice about that.  better to have both at one location and maybe splurge for a 3rd node or a VSA license to do remote replication to... it will likely still be cheaper to do than the bandwidth costs for multi-site setups.

oikjn
Honored Contributor

Re: Physically moving Multi-site Cluster to Single site

how long will it take you to move the two nodes?

 

I"m suprised CMC lets a virtual manager run in this situation, but I guess it is easier to recover than a FOM at one site when that one goes down...  anyway, assuming the time offline isn't too much, you should stop the managers on both nodes you plan on shutting down so that the management group ends up with two managers and a VM for quorum.  If you leave the other two on, then you won't maintain quorum if either additional node fails.  Then you might as well just shutdown both nodes and move them together to the new location and turn them back on there.

The catch is that all your NR10 nodes will be running unprotected during that time.  If you have the space in the SAN to convert as many LUNs as possible to NR10+2 first, I would do it so at least those nodes will stay 100% protected during the transition.

 edit:  if you have extra hardware to create two VSA nodes, you couldmove the physical nodes without exposing any risk to the data by using the trial VSA licenes to exchange the nodes... its a little complex, but less risky to the data, but requires you have VSAs capable of handling the size and load of your SAN.

MichaelGruber
Occasional Contributor

Re: Physically moving Multi-site Cluster to Single site

Thank you for your reply... actually, I added the nodes from the Sites link and that did the trick.