RE: Active/Active Site A/Site B using SRDF

From: Matthew Zito <mzito_at_gridapp.com>
Date: Wed, 4 Apr 2007 10:22:46 -0400
Message-ID: <C0A5E31718FC064A91E9FD7BE2F081B1B97558@exchange.gridapp.com>

Yeah, there's no good way to do that at a storage level - you can *replicate* datafiles using SRDF, but the far side will be marked read-only. You could do bidirectional SRDF, so something like

db1 (source) ------> (readonly copy of db1)

(readonly db2) <------ db2 (source)

*array 1* <---------------> *array 2*

But bidirectional SRDF requires, as I recall, dedicated fibre channel ports in both directions, so you use more IO and use more channels, and you STILL don't get data synchronization. I have seen some products claim to allow bidirectional read-write synchronization, but I can't imagine the performance impact isn't devastating.

Matt

From: oracle-l-bounce_at_freelists.org
[mailto:oracle-l-bounce_at_freelists.org] On Behalf Of ryan_gaffuri_at_comcast.net

	Sent: Wednesday, April 04, 2007 9:05 AM
	To: Matthew Zito; oracle-l_at_freelists.org
	Cc: Matthew Zito
	Subject: RE: Active/Active Site A/Site B using SRDF
	
	
	 
	I think the original plan is to actually have two sets of

database files on two sites. I dont see how that can possible work with oracle unless there is some kind of two way mirroring you can do with a SAN across a fibre, but I doubt it.

Original message -------------- From: "Matthew Zito" <mzito_at_gridapp.com>

EMC SRDF does not support active/active with neither synchronous nor asynchronous configurations. When you have an SRDF environment your R1s (near side) are writeable while your R2s (the far side) are not.

If you want to do active/active sites, you can do a RAC stretch cluster using either long distance Fibre channel (bleh) or iSCSI
(much better), or you can do things at an application level. .

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Received on Wed Apr 04 2007 - 09:22:46 CDT