Question : Problem: replication SAN vs. VM vs. SQL vs. file - for DR site

Hello

We are in the process of deciding upon a replication strategy for our DR site.  I am interested in learning the limits/advantages of one replication technology vs. another.  We have an Equal Logic iSCSI SAN in both corporate and the DR site, interconnected by a 6Mb WAN link (which could be upgraded if necessary).  We are in the process of migrating as much as possible to VMware, though I suspect not all will make the transition.  We've got about 350 users (but I can't give you a quantity of data to replicate just yet).  We run some typical apps like Exchange, Sharepoint but a lot of vertical apps that are mostly backend with SQL or flat files.  The root question is, "how should I replicate my data to the DR site".  To the best of my understanding we can use replication at the SAN / VM / SQL or file - level.  We also have a Riverbed WAN optimizer for compression of data.  I'd imagine one scenario is to virtualize everything and use either SAN replication or somthing like Vizioncore for VM replication.  

But do all applications support SAN replication?  
Is SAN replication not compatible with, for example, a running VM at the DR site?
Would the VM need to be turned off and not in use in order to replicate to it?  
Does a WAN optimization product help improve bandwidth utilization at the SAN level?

It seems that SAN replication would be the easiest to deploy as a one size fits all solution.  If I am not able to use SAN replication for all applications,  how feasible is virtual machine replication?  Can you only replicate the deltas with this technology?

I guess more questions would be generated if the answer to "does SAN replication work for any application" question is "no".  But rather than going on with irrelivent questions, I'll wait for some guidance.

Take this issue from the perspective that there are some technologies in place, but the nuts and bolts of replication are only just starting to be reviewed.  Your feedback is greatly appreciated!!!

Answer : Problem: replication SAN vs. VM vs. SQL vs. file - for DR site

Hello,

Well I would go with SAN replication. In order to implement it well, I do not know about 6Mb WAN link. This can be satisfy some needs, but real-time replication I do not know. Usually in this kind of scenario I would recommend Fiber Optics and one Leased Line as witness link.

In order to implement Disaster Recovery you need to tell us the following:
1. What amount of downtime is acceptable
2. Is the same equipment used on both sides
3. What are you using for virtualizing ? (VMware ESX or VMware Server)
4. Can you afford Fiber Optic interconnection
5. Would you prefer active/active site or active/passive site
6. Real-time synchronization or synchronization when the links are not being used and when there are no users present in the network
7. What type of backup do you use (Software backup, eg. Veritas, Data Protector etc...).

Best regards,

Predrag