vSphere - Storage question (Fiber and iSCSI)

[sdog]

I have a 2 node ESX 3.5 cluster (planning on upgrading to vSphere 4.0) connected to a Dell CX3-40 SAN via fiber. I also have 2 stand-alone ESX 3.5 hosts with local storage

All the hardware is the same - Dell PE2950's with same/compatible processors.

My questions is can I configure the STANDALONE hosts for iSCSI connections to the DELL CX3-40, add them to the cluster, creating a MIXED iSCSI/Fibre cluster?

My guess is yes, because each host just needs to be able to access the shared storage.

Thoughts, recommendations, or past experience with this?

[AntonVZhbankov]

Just to clarify: do you want to connect hosts via iSCSI and Fibre Channel to the same LUNs or different LUNs?

---

VMware vExpert '2009

http://blog.vadmin.ru

[sdog]

I would like them to be able to access the SAME LUN's so I could provide HA for all VM's in the cluster.

[AntonVZhbankov]

I suppose this is not a good idea, although it can be possible.

---

VMware vExpert '2009

http://blog.vadmin.ru

[sdog]

Do you know what the risks might be?

I figure each HBA in a host is unique and each host has a different physical path. Using iSCSI for a new host would only introduce a new path to a shared LUN.

[bulletprooffool]

If the SAN supports both iScsi and FC, then there are no problems.

The only issue is that if Host A is connecting over iScsi and Host B over FC they will see the Luns as 2 DIFFERENT datastores, so you could end up not being able to vMotion between the Hosts - or even worse, you could end up accidentally trying to sVmotion from a Lun attached by iScsi, to the same Lun attached by FC.

The UID generated for the Datatstores WILL be different!

[sdog]

Your reply does make sense, but I'd like to know for certain. Has anyone ever tried to do this or know for sure if its possible or not?

Thanks

[awliste]

I've pulled this off before - it wasn't the greatest solution, but I was pressed for results and had to do a SAN-to-SAN fully copy without disruption.

I ended up taking a standalone host, connecting to the prospective SAN via FC, then making an iSCSI connection to the target SAN.

It worked, but it was not pretty. Made for a long weekend, and definitely one of my more pointed lessons in playing in this field.

Good luck man.

- abe

[sdog]

Im actually trying to find out if i can maintain a PRODUCTION ESX cluster with 2 FC hosts and 2 iSCSI hosts. I would like to have HA/DRS + storage vMotion.

The 2 FC nodes are already in a cluster. I would be adding in 2 iSCSI hosts, removing their DAS enclusures and putting their VM's on the SAME luns as the FC hosts.

Doesnt sound too promising.

[RParker]

The 2 FC nodes are already in a cluster. I would be adding in 2 iSCSI hosts, removing their DAS enclusures and putting their VM's on the SAME luns as the FC hosts.

What's with the mixing and matching? If you have Fiber, why not make them ALL Fiber, why introduce new technology? If you KNOW that Fiber will produce a UID different than that of iSCSI on your PRODUCTION systems I wouldn't risk it.

Make them ALL the same topology, that way you KNOW what you are getting, and not doing a what if on your critical stuff.

Or better yet, set up a lab, and TEST it FIRST!