adding disks to computing nodes in a diskless cluster

mahmoodn · 12-28-2012, 02:38 PM

We have a diskless cluster. The problem is that the server node has 6 disk modules and all of them are full. On the other hand computing nodes have free slots (because they are actually a complete system which we removed their disks). Is there any way to attach more disks to computing nodes and then mount them in a magical way on the server node?

jefro · 12-29-2012, 10:39 AM

Kind of an odd way to do it. Normally you would want to be sure data is available just like the drives are in the server. If a node were to be out then the data would be unavailable also.

If you have to then you have to also.

One might mount the drive as any number of networked drive might be mounted. Some special coding might be needed to be sure the exact node were to mount it in the same way each time. Iscsi and nfs are two choices I'd look at to begin with.

mahmoodn · 12-29-2012, 11:32 AM

Is there any alternative? Let's say we some nodes where each is a complete system. How can we make a cluster?

btmiller · 12-31-2012, 04:52 PM

You could always use a cluster file system like Red Hat GFS, Lustre, or Ceph to do something like this (at the most primitive level, you could even just use NFS or even set the disks up as iSCSI targets). However, if you go this route storage traffic on your cluster LAN can and probably will interfere with compute traffic. Plus, you will probably have trouble re-sharing disks that are themselves mounted remotely to the head node. In my opinion, if at all possible you need to buy a higher capacity head node.