Re: Replicating Live Oracle DataFiles/LUNs to remote site via SAN tool?

From: Nuno Souto <>
Date: Fri, 28 Aug 2009 00:56:42 +1000
Message-ID: <>

Taylor, Chris David wrote,on my timestamp of 27/08/2009 11:42 PM:
> Any of you guys/gals replicating LIVE datafiles from one SAN to another
> in a remote location?
> We're looking at using HP's CA tool to replicate LIVE datafiles across a
> WAN to another SAN. The replication is block based, so any block that
> changes on the primary LUN is immediately replicated to the remote LUN
> at the remote site.
> Is anyone doing anything similar to this? Pros? Cons? I have a hard
> time imagining that this is a good idea but perhaps it is doable.

Wouldn't have a clue about the HP solution. Replicating our DW db at the moment using EMC's Clarion synchronous replication over a dark fibre network to a DR site. 1.5TB size.
The major determinant for it working is to have ALL luns for your db in one single synchronous replication group. More than one group and you'll have a corrupt replicated db.
Synchronous SAN replication involves a performance penalty on ALL writes, not just data/index writes. Ie: temp and undo, all get written to both sites. That means: wide pipes needed. Ours does 400MB/s aggregate total and is *just* enough at the moment.

About to start exploring a Dataguard alternative in September, to reduce the amount of data we have to send. The cost of upgrading that 400MB/s pipe is stratospheric, while with DG we only have to send 500GB of logs a day and we can wear a small delay in synch. Means maximum performance option of DG is fine.

Nuno Souto
in sunny Sydney, Australia
Received on Thu Aug 27 2009 - 09:56:42 CDT

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