Crash consistent snaps of Exchange on PS5000 SANs

The conversation below happened yesterday and was connected to an older posting on my Storage @ Work blog on EqualLogic's site. I thought the content was good so I copied it below for readers at InsideIT. Stan is the external commenter and Darren Miller is an excellent  product guy and SME who responded to Stan's questions.

FWIW, Darren has a couple upcoming online Demos that I recommend, including today 4/17 at 3:00PM Eastern


Posted by stan | April 16, 2008 11:36 AM

In the past I was advised that Equallogic SAN replication was not "crash consistent", that is since many server apps hold data in RAM buffers/cache , the data on the SAN is not complete, thus replication to other SAN's sends incomplete data. To workaround this problem the SAN needs software running in conjunction with the server to sync the data in the buffers/cache to storage.

Does Equallogic do this now? How does it and where could I read the details of this? I'm interested in how crash consistent Exchange, SQL, windows AD and assorted VMware vm's with custom apps are.


Posted by Darren Miller | April 16, 2008 4:39 PM


To address your questions and concerns, Auto-Snapshot Manager (ASM), is included in the Dell EqualLogic Host Integration Tools Kit. ASM integrates with Microsoft VSS and the EqualLogic VSS provider service to create application consistent copies (Smart Copies) of data on Win server 2003 systems.

The way it works is you would install the Host Integration Tools kit (downloadable at on your server making sure you select Auto-Snapshot Manager as part of the install package. Once installed you authenticate the host to the PS Series SAN through CHAP authentication. Once all configured, ASM will be able to protect data on the host.

ASM facilitates the volume protection capabilities of the PS Series SAN like snapshots, clones, and replicas but integrates directly with the application through VSS to ensure data consistency. You as the user determines what type of Smart Copy to create beit snapshot, clone or replica.

For more information on how you would use ASM with SQL Server databases there is a detailed technical report describing this functionality on

In terms of VMware protection, there is a lot of information out on the site with different examples of how to protect your VMware environment on a PS Series SAN.

About the Author: Marc Farley