Storage Unit Group eligibility

[mdmiles125]

I have 2 Basic Disk (Disk Staging) Storage units in a Storage Unit Group,   I need to increase the size of this storage.   Can I add my Tape drive storage units to the group while I take the disk units down ?

[mdmiles125]

I might also add that we are reconfiguring the basic disk into different chunk sizes to affect performance

[davidmoline]

It doesn't really make sense to add a tape STU to an existing disk STUG. 

You indicate there are two disk STU's. Can you do one at a time, so leaving the STUG available?
The other advantage of this, is if something goes wrong during the resizing process you will still have some storage available (this is me being risk adverse).

[mdmiles125]

THank you for your response.  However, the disk is actually  being shared by 3 media servers, and because of performance issues, we have to remove it and just allocate a chunk to each media server.   WE plan to destage all of the images to tape, and then add the tape storage unit to the Storage Unit Group before we remove the disk and re allocate it

[davidmoline]

In which case, I don't believe it will be a problem adding the tape STU to the group (even if this is unusual). 

You may want to change (temporarily) how the STUG is managed (from load balanced to prioritised or failover as required, but possibly not necessary) to give more predictable behaviour.

How are you currently "sharing" the disk between three media servers - CIFS? and do they have their own separate folders to write to? Do you intend to continue this moving forward, or move to dedicated direct attached stsorage (which would provide the bst performance).

[mdmiles125]

Thanks again for your input.   Yes, it's the same storage, and each media server has it's own folder.   Currently we keep 90% of the data on the dsik, and de-stage at 95%.   The plan is to start keeping 80% on disk, then 70 % ... until we get down to zero.   Then once everything is migrated to tape, we will suspend scheduling, add then add the Tape storage units, then remove the disk, resume scheduling, reconfigure the disk, add them back to the group suspend scheduling again, and then remove the Tape storage units