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Adding to Cluster

Steve McGee
Occasional Advisor

Adding to Cluster

We purchased the P4500 10.8TB SAS Virtualization SAN here a while back. I'm interested in adding a node to it, but all the SKUs I see are for the G2 models..

Does anyone have any experience with adding a G2 node to their non-G2 cluster?

I understand the conformity requirements for size and adding anoter 5.4TB SAS storage node should give me my third node and allow me to do Network Raid 5.

This should also essentially double my usable space switching from NW Raid 10 on 2 nodes to NW Raid 5 on 3 Nodes right?
Honored Contributor

Re: Adding to Cluster

As far as I am aware you can add any node to any cluster however:
1: you should not mix sas with sata with VSA
2: you should think about potential performance issues if mixing different h/w
3: if the node you have in has MORE capacity than any existing node in the cluster then you WILL NOT be able to use the "extra" capacity of that node. You will be stuck at the smaller size - this is called stranded capacity.
Note - if you add a smaller node into a cluster then it will go to the smaller size !!!! You have NO choice in that!
You need 4 nodes (min) in a cluster to do network raid5. I think from your post you will only have three ??
if you have nothing useful to say, say nothing...
Bryan McMullan
Trusted Contributor

Re: Adding to Cluster

4 nodes is the requirement for Network RAID 5 (3 data and 1 parity).

I don't think you'll double your space really if you moved to RAID 5. The benefit is in the snapshot area. Your workload should be kept in mind as well, you don't want to use NW RAID5 for highly transactional workloads.
Mike Povall
Trusted Contributor

Re: Adding to Cluster

Hi Steve,

The G2 units work fine with P4500 originals. I have a cluster of five 3.6TB SAS units, three of which are P4500 and two are P4500 G2 all running SAN/iQ 8.5.

The capability to do Network RAID 5 on three nodes I have heard will be possible with SAN/iQ 9 but there is no gaurantees.

Regards, Mike.