Snapshots of Clones

With RM, when you perform a clone job, this is the sequence
1) RM sync's the clone to the source lun
2) RM quieces your app
3) RM fractures the clone from the source lun
4) RM mounts the clone (when required, either as part of the job or on-demand)

If you manually performed a sync in Navisphere, then you would need to manually fracture the clone.

RM never keeps a clone syncronized to a source LUN.

Hope this answers your question.

Correct, it is not kept syncronized.

RM with Clariion technology gives you point in time, golden copies.

Say you have data or logical corruption, your clone is also poisoned.

If you want to keep a clone syncronized, then its meerly more seen as source protection, but thats what Raid gives you.

Do you have a specific requirement to keep a clone syncronized? I just need to understand why you would want to do this.

Cheers
James.

Not from within RM. And not good practice to be doing so really when the snapshot source is a clone itself.

so even if i create a clone and not mount it, thats not kept synchronized with the source?

I thought it would be synchronized with the source until it was fractured?

OK

So lets say i make a clone of a lun, then mount a snapshot of the clone

i then resync the clone, what happens to the snapshot?

When you take a snapshot of that clone and mount it, can the clone be mounted also?

OK thanks

Where i was going with this was, i see there is an option to Mount snapshots of Clones, but not sure how you are able to use that option or how it would be beneficial.

Can you expound on that option?

Ah yes, of course!

Right, you take clone of source LUN X at 13.00. RM fractures the clone.

You mount the clone, and you do want to make some changes, but you do not want to make ANY modifications to the golden copy, ie the clone lun.

RM allows you to do this by creating a snapshot from the clone, and presenting and mounting that snapshot to the mount host. The host never sees the clone!

Its a great feature, also previously know as "Disgard changes on unmount"

RM automates the whole process for you.
Hope this explains it?

Cheers
James.

On a CLARiiON the snapshot will remain mounted and the data that changes on the source clone will be written to the Reserved LUN Pool. So the snapshot is persistent across clone synchronizations. But you have to be careful with this as you have the potential of filling up your RLP.

On a DMX snapshots of clones are not persistent and RM will dismount the snapshot from the mount host and expire the snapshot before synchronizing the clone.

I have a related question for this thread. With snapshots, you are limited to an 8 lun max for consistent split. I don't see an option for consistency method when you take a snap-shot of a clone.

We want to do this with our large production database that is made up of 11 luns. I'm doing a consistent split, non hotbackup mode clone of our Oracle database and not mounting that clone. When I try to snap that clone it is failing due to the number of luns being > 8. I check the job to change the consistency method and there is no option to change. Is it inheriting the consistency settings from the clone?