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CommVault, DataDomain, and copy to tape

Hi All,

I have the following challenge:

I have two DD4500 appliances - one in Production location and one in DR location. At each location I also have a CommVault 10 server running on win2k8 R2 that is connected to the DD appliances via CIFS protocol. There is MTree replication between the DD appliances - in one direction - Production to DR. I am trying to find out if I can offload to tape data that is replicated to DR using CommVault server at this location. If this is doable, what do I have to do on DD to make the replicated MTree accessible by the CommVault server, and what do I have to do on CommVault so it can read the data. Does EMC support this type of configuration?

Appreciate your input.

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4 Replies
ble1
5 Iridium

Re: CommVault, DataDomain, and copy to tape

As replication is done at DD level (so no boost or any other communication back to backup application), this means that replicated data can be used by backup application only in exclusive mode - meaning either you use your primary backup or replicated one.  You can't have both at the same time as backup application would be confused about location.  As far as I know, only those backup applications that use ddboost and have replication under backup application control can use replica and have that one moved or copied to tape further.

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Re: CommVault, DataDomain, and copy to tape

I do not quite get what you mean. Please elaborate more. Are you saying that there is no way I can present the replicated data via CIFS to a different backup server (it is not going to be a production backup server)?

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umichklewis
3 Zinc

Re: CommVault, DataDomain, and copy to tape

I think Hrvoje is saying that the same application can't see the same data from the same backup server in two locations without being involved in getting the data there itself. 

In your case, however, I'm not sure it will work without some manual intervention.  How will the CommVault server at DR be aware that new backups have landed in the CIFS share?  Does CommVault poll a location for new data?  If so, that should work.  Otherwise, you'll need some method to notify the server to scan for new backup images to roll off to tape.

Another sticking point - the replicated mtree will be read-only (you can see this as 'RO' with 'mtree list').  If CommVault needs to write to this location as part of the tape out, however, that will probably fail.


Does that help?

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ble1
5 Iridium

Re: CommVault, DataDomain, and copy to tape

ad_astra wrote:

I do not quite get what you mean. Please elaborate more. Are you saying that there is no way I can present the replicated data via CIFS to a different backup server (it is not going to be a production backup server)?

It all comes down how CV is handling this.  You said you wish to use second server to offload tape out, right?  Data you have on second server is replica of first active server - can you load it under different name of server?  If yes, fine.  If not, then it means you must shut down active server which I doubt you want.  Next, if you tape out on secondary server how does primary become aware of that.  There is a great deal of advantage when replicas are integrated in backup application, but as far as I know this is not the case with CV.

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