Running redundant ESXi 4 servers attached to HA Virtual SAN appliance

[andybutler]

I have a hypothetical question. I would like to setup two ESXi 4 Servers (the free version - not using vCenter) with the datastores that reside on a virtual iSCSI SAN running OpenFiler with HA DRBD replication. Essentially the way it would be setup is the first ESXi Server (ESXi-VS1) would be setup exactly the same as the secondary ESXi server (ESXi-VS2). Each ESXi server would run an OpenFiler SAN appliance VM that are replicated to eachother via DRBD and heartbeat HA.

The primary ESXi server (ESXi-VS1) would have it's main datastore for all VM's running on it on the local primary VM SAN, Openfiler1. Any changes to the Openfiler1 SAN would be replicated back to the secondary Openfiler2 running on ESXi-VS2. The concept is that if ESXi-VS1 were to completely go down that I would have a live replicated backup of all the VM's that are replicated to ESXi-VS2's OpenFiler2 VM SAN and be able to bring all my VM's back up online with minimal downtime by importing them into the inventory of ESXi-VS2 and turn them on. Consider it another version of the poorman's VCB if you will. I'm wondering if this in theory would work.

Another option I was thinking is that I could have the datastore that ESXi-VS1 uses running on Openfiler2 as a primary SAN (which is on my failover ESXi-VS2 server) and have Openfiler1 running on ESX-VS1 running as a secondary HA SAN appliance. That way if the Openfiler2 SAN running on ESXi-VS2 were to go down it would immediately switch over to the locally running secondary VM SAN running as Openfiler1 on ESXi-VS1 and have no downtime. Alternatively if ESXi-VS1 had a complete failure I could still import all of the VM's that ran on the primary Openfiler2 SAN into the VM inventory of ESXi-VS2.

Would this work? I'd love to be able to afford a fully redundant physical SAN to accomplish this level of failover protection but I don't. Please let me know any suggestions or alternatives would see with this setup. I'm wanting to run Exchange 2007 and Apache as VM's on these ESXi servers.

[AntonVZhbankov]

Yes, it should work.

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VMware vExpert '2009

http://blog.vadmin.ru

[DallowSpicer]

Hi Andy,

I was just wondering how far you'd got pursuing this? I am also considering virtualisation and using a very similar setup to you. My main concerns with it all are performance for Exchange 2007 and our Unix database server and also how to backup the VM's. I can't afford a SAN on my budget either but have been considering an Iomega ix4-200r NAS, Starwind iSCSI virtual SAN software or OpenFiler. I'd really appreciate hearing how you are getting on.

Best Regards.

Kevin.

[Hillel_s]

Hi Andy,

Also wondering how this has worked out for you. Just to get this straight, in each ESXI server, you have the local disk defined as a datastore, a single Openfiler VM taking that datastore, and then creating a new SAN datastore from within the Openfiler VM? Seems interesting. Have you considered spreading the load a bit for active VMs on both ESXi servers, each replicating to the other's datastore? I would like to consider a similar setup, but with one Windows DC in the first ESXi server, and a second DC in the second ESXi server, with datastore replication going both ways.

[AnsgarOnTVE]

Hi Andy!

Last week I installed a similiar setup using Xtravirt Virtual SAN. But at the moment I am disappointed by the performance.

Installation went without a problem due to the step by step installation guide. BothVirtual SAN appliance are linked by a separate 1 GB nic.

Initial synchronisation used a bandwith of abt 80 MB/s which is fully acceptable. So there doesn't seem to be a bottleneck on that link.

Copying the first VM (Win XP) to the new Virtual SAN datastore took much longer as aspected. I didn't do any measuring at that time

After that I did some testing by copying some files from and to our file server. That yielded a datarate of abt 15 MB/s reading from the local drive

(i.e. from the virtual SAN) and writing that to the file server. Doing it the other way round I only got 7 MB/s.

These figures are far too slow to be used in a production enviroment.

Sofar I have not been able to pin down the bottleneck. Any hints on this topic are welcome.

Best regards

Ansgar

[FAsTec]

I tricked the issues by doing a simpler setup with XenServer by Citrix and DRBD. Only two computers, no iSCSI, no SAN.

This because I started my project with vmware server 2.0.2 64bit on ubuntu 64 bit, but its performances were close to zero.

Just to let you know: one single and lonely windows 2008 guest was completely unusable, either if the hardware was a real and well equipped IBM X3400 M2 server.

It was may. I started over and now it is working fine with xenserver. Hope that vmware updates (sooner or later) the server for linux with a more performing one, but as far as I know, they abandoned it.

Robert

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