What's the difference between a Snapshot and a SmartClone?

[Christian Reiter]

Hello!

After studying the HP P4000 documentation files, I'm not quite sure what the difference between a Snapshot and a SmartClone is.

As far as I've understand the documentation, a SmartClone can be mounted like a independent volume (read- and write-access is possible). The documetation also says, that a Snapshot can be mounted as read/write-volume too.

So what's the real difference?

If I understand correctly, the source volume can't be deleted in both cases.

Best Regards,
christian

[Uwe Zessin · Accepted solution]

A snapshot itself is always readonly, but it can be made look like writeable by providing another layer for storing changed blocks - just like the production volume mapping. The writeable snapshot layer is called a 'temp space'.

A smartclone is a snapshot with multiple 'temp space' layers at the same hierarchy which are presented to different iSCSI initiators, e.g. desktops or training systems.

[teledata]

In reality smart clones are using the same snapshot technology, yet simplifying the management to allow for persistent changes to stay with the "smart clone" without having to manually commit the temp space.

This article gives a good detail about how the SmartClone feature works:

http://www.tdonline.com/hp-lefthand/smartclone/

[Christian Reiter]

Thanks to both of you for the explanation!

[certangle]

May I know the difference betwwen vsnap and Snap shot?

kind regards

[Uwe Zessin]

"vsnap" is EVA's terminology for a thin-provisioned snapshot.
I haven't seen this term in the P4000 world.