SAN Replication for Fault tolerance

[daugavpils]

Hi Everyone,

I hope that someone would point me in the correct direction - it looks like I have no enough konwledge in the subject and timeframes are too tight for me to explore different scenarios in depth..

We have two datacenters few miles away from each other connected by 100 Mbps link.Each datacenter will have 5 BL490 blades with ESX Standard hosting about 50 VMs. Eac hsite has HP eva4400 SAN with SAN replication set up.VC is going to be in the first datacenter and both datacenter are networked.

SAN Replication is block level so it seems like I cannot just replicate changes but all writes would have to be replicated.This should not be a problem as link can sustain about 1.8 TB a dayand data can be buffered.

I am having trouble however visioning how recovery would work in this case.We don't need instant recovery , I would say 4 hours recovery time is accepted so fancy automatic SRM like DR scenario would not be easily accepted due to the financial reasons, however any comments are welcomed.

Current idea is following: replicate LUNs from primary site to the secondary.When disaster strikes, IT personnel switches on ESX hosts on the remote side and connects replicated LUNS to them, then registers VMs and changes IP address.

I understand that this seems like horribly manual process and I almost sure I have missed some obvious pitfalls here.

Could someone let me know what direction should I go?An articles regarding the subject?

This is a brand new setup and we would rather build up basic recovery process and scale it later.I just need to have a right direction to allow for such scalability.

Thank you very much in advance!

[kac2]

i think you have a good grasp of how it should work This is something I would implement but use Veeam as the replication medium. Here is what I would do for the VM IP Addresses. I would like to keep the same IP addresses because I'm sure not every single VM uses DNS for all its applications, databases, etc. So unless you are POSITIVE you covered all your DNS bases, i would try to use all the same IP addresses. You would just need to work on the routing part of it all before you fire up your VMs. So make sure when you either fail over or test your VM failover, you make sure that if you have a VM with IP address 10.10.10.10 at both Datacenters A & B, the routing would make sure all your clients can't talk to datacenter B until you make that route active. This way you can test your failover