HPE EVA Storage

Business Copy on EVA4000

 
pymsh
Frequent Advisor

Business Copy on EVA4000

Hi,
I have a EVA4000 with Business Copy enabled on it.
I have made a VDisk and a Snapclone for it, but these two volumes don't work as synchronized volumes.
I think when I make a change on the main volume, the cloned volume must be quickly updated in time.
Do I have to make some configuration or changing on EVA or any thing else?
Thanks.
5 REPLIES 5
Uwe Zessin
Honored Contributor

Re: Business Copy on EVA4000

I'm sorry, but you have completely misunderstood how snapshots and clones work:

Their purpose is to give you a consistent 'copy' of the original data from a certain point in time (=when you started the snaphsot/clone). The copy MUST NOT be altered by any more writes to the original volume! A server that has mounted the snapshout/clone would become very confused when somebody else makes changes to the file system.

This is a bit like you were writing a book and made photocopies to a friend for reading. The friend can make changes to his copy, but you won't see it in your original and the friend will not see your modifications unless you made new copies.
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Víctor Cespón
Honored Contributor

Re: Business Copy on EVA4000

Hi, you need to use a mirrorclone on that case. A mirror clone is a clone that keeps being synchronized to the source vdisk. Until you "fracture" it. Then it becomes a point-in-time copy, like a regular snapclone.
But you can synchronize it again and it will copy the changes done to the source vdisk.

Mirrorclones are available on latest versions (XCS 6.1xx and above) of the EVA firmware.

Check RSM user guide, it explains Bussiness Copy and Continuous Access pretty well

http://bizsupport2.austin.hp.com/bc/docs/support/SupportManual/c01680899/c01680899.pdf

Chapter 10 - Virtual disks
pymsh
Frequent Advisor

Re: Business Copy on EVA4000

Thanks for your attention!
I want to have a exact copy of a EVA volume on another volume.
How can I do this?
Uwe Zessin
Honored Contributor

Re: Business Copy on EVA4000

With a clone. What you cannot have and will not work (as I described above) is a copy, presented to a second server, that is automatically kept current when the first server makes changes.
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Víctor Cespón
Honored Contributor

Re: Business Copy on EVA4000

Snapclone: A copy of the vdisk in the current state, does not copy the changes from now on.

Mirrorclone: makes a copy and keeps it synchronized until you manually fracture it.