Disaster Recovery Site Replication

[alhamad]

The scenario goes as this:

Two ESX 3.0.2 servers with VMotion, HA and DRS enabled.

20 VMs stored in two LUNs

Both LUNs resides in HP EVA 4000 SAN

My questions are: how to achieve a replication of all VMs to the DR using SAN replication? Will it work? Did anyone try it? Is this the right way to construct a DR?

[Texiwill]

Hello,

There are a myriad of ways to create a DR site. SAN replication is one possibility. However, with SAN replication your VMs at the DR site are only crash consistent copies. And in many cases that is fine. Many many companies do this with no issues.

esxRanger, VCB, and other Virtualization backup tools will use ESX snapshots to get around the crash consistent backup issue and produce cleaner backups with quiesced data on the disk.

Best regards,

Edward

[GavinJ]

The EVA using Continuous Access functionality on the LUN's actually does this pretty well. It doesn't quiese the VM's but provides a pretty good crash consistent synchronous replication for DR. Obviously need another SAN at the DR target to receive the writes.

Another possibility is Vizioncore ESX Replicator - I haven't used it yet myself but understand that the new version has resolved quite a few issues of the first one.

Gavin

[petedr]

esXpress backups has simple replication in its 2.5 product and will be in Beta for their 3 product shortly. Basically it takes backups from the source host and then applies them on the DR host. This works with their Delta backups as well as Fulls.

[BigHug]

Hi, Gavin:

Can you elaborate a bit how EVA can be crash-consistent without quiescing the VM? Is it kinda hit-or-miss? Or it can guarantee the crash-consistency?

[GavinJ · Accepted solution]

Crash consistency is the default state if you were to pull the plug on a virtual infrastructure, in the same way as a snapshot is used to take a backup copy of a VM - there's no agent flushing the buffers and sequencing graceful application shutdown like MS VSS integrated apps can be configured, eg: EMC Clariions using Replication Manager.

For the EVA using CA for synchronous mirroring is pretty much the same; there's quite a good paper by Hp which describes a DR set up for VI3 infrastructures: http://h71028.www7.hp.com/ERC/downloads/4AA1-0820ENW.pdf

[alhamad]

Thank u GavinJ 4 d whitepaper it answered my queries

[kix1979]

Correct, Replicator is much better then our previous 1.0 product. It allows you to do similar replication to SAN based technology. We replicate on a per VM basis at a block level. The main difference between SAN LUN replication and us is that we are a little more granular, so you can replicate just the business critical VMs, but it also does the work that you need on the back end like registering the VMs and making changes to the VMX files as needed.

[pkratz]

Hi alhamad and GavinJ,

I need to get that running as well but the Link doesn't work any more. Can you upload the file?

Did you gat it running?