Mixing different Isilon node types

Peter is definitely correct in his response, and the node equivalence reference is appropriate.  In order for data layout, processing and data protection to function, it is important that the nodes match in their storage capacity within a pool.  You can mix whatever you like across pools, but at a minimum of 3 nodes so that the N+1 minimum protection still functions within the pool.  Varying the capacity of the nodes just makes the data balancing act nearly impossible, thus the limitation. 

Peter is correct but there are multiple ways to handle your different node types.

You can use SmartPools to move files between storagepools

You can use SmartPools to put both pools in a tier

You can use # isi set to define a root directory for files that belong in one pool vs the other

All of my customer-facing clusters have multiple pools - typically a primary tier (eg S200)and a secondary tier (eg NL400).  I've got one cluster with 3 pools since I have some X400 nodes in there too.

With older nodes, you'll have to pay attention that the version of OneFS you want to run supports all of the node types.  Some newer nodes (eg S210) have minimum OneFS releases and I wouldn't be surprised to eventually see old node support dropped from newer releases of OneFS (if it hasn't happened already - I haven't done any research on this to see what EMC's policy is since it doesn't affect me).

As you move nodes from cluster to cluster, also be careful that you don't slowly grow your pools by 1 or 2 nodes at a time since that will cause a lot of rebalancing to occur and can result in nodes to run out of space even though a new node has lots of free space.  If you can, try to add at least 3 nodes at a time, even if you already have 3 to start with - that forces new writes to go to those 3 nodes.  If you add just 1 node, until the space is balanced, new writes will go to 2 old nodes in addition to the new node.

Ed, this will not work for the original plan, two distinct  4-node clusters formed as  AAAB and BBBB...

You may also find this recent blog posting helpful if you're new to SmartPools or unclear on how weird it can be:

https://community.emc.com/community/products/isilon/blog/2015/01/05/understanding-smartpools

Thank you all.

ed.wilts schrieb: Mix, yes, but with a 3-node minimum for non-equivalent node types.

That is the most important answer to me and I will keep in mind:

• If I add a node type that is already part of the cluster than I can add only one.
• If I add a node type that currently is not yet part of the cluster I have to add at least three of them.

What would happen if I do this nevertheless?

Will the joining process abort? Or will the joining process pass but the one new node is not usable?

Yes, it will join the cluster but left "unprovisioned" until two more buddies join to form a new pool.

Hello Everyone,

My question is a little different but permit me to ask here.

I have two NL400 nodes running different OneFS versions.

Can I replace components on these nodes without encountering problems because of the different OS versions?

Thank you.

Hello jessieobioma,

In most cases as long as you are using NL400 components you should be able to replace them without any issues.  What is the versions of onefs are you using?