Moving from one ESXi to two with SAN

[jmapt]

Hello,

We are moving from a single ESXi server to having two ESXi servers and are adding an iSCSI SAN. All references to ESXi are meaning v4.

The first question we have is, what is the best procedure for moving from the local datastore on the original ESXi server to the SAN? Our guess was to just shut down the VMs then migrate the data using the datastore browser in the vSphere client. Then afterwards reimport on the host using the disk files that are now on the SAN. Is this the best/approved way?

Next we are wondering about the iSCSI throughput. My understanding is that there is no real good way of bonding the links yet to get higher throughput. So we were going to have an 8-port gigabit switch that will have 4x1Gbps network links to the SAN, and then 2x1Gbps links from each server to the switch which would all be its own subnet. We are exempting the second switch at this point eventhough it would be nice for potential failover, due to budget constraints at this point. The NICs we are proposing using are the Intel Pro/1000 Server MT and PT nics with dual ports (one per server) mixed with onboard Broadcom NetExtremes (one of the 1Gbps links to each NIC in case a NIC fails). Does this all make sense or is there a better proposed way of doing this?

I think that is the main questions for now, just new to the SAN idea and have done as much reading online as possible but there seem to be so many variances between v3, v3.5, and v4 I just want to make sure I have it all clear so far.

Thanks!

Josh

[Luckybob]

Everything you have mentioned looks good. Moving the VMs from local datastore to the SAN and doing an import will work just fine.

As far as the iSCSI setup on the ESXi Host, your proposed setup should work, it is the same way we currently handle it.

[jmapt]

Was there anything special you did in terms of vSwitch configuration on the hosts or anything to load balance the two 1Gb connections to the SAN or did you just pretty much use defaults?

[Luckybob]

I setup an additional vSwitch for the iSCSI traffic. Each of the NICs goes to a different layer 3 switch that is setup for HSRP. This way we have full redundancey for our SANs. As far as the vSwitch or portgroup, that is set to default.

[TobiasKracht]

1Gb link from server to SAN is absolutely affordable solution in most cases. Either "all by default" also working good.

StarWind Software R&D

[hstagner]

Hello Jmapt,

What version of vSphere 4 do you have? Or are you using the free ESXi version? If you have the Enterprise version, it comes with storage vmotion. This will allow you to "live migrate" the VM's from one datastore to another. If not, then yes copying and re-registering the VM's will work.

As for the SAN, you are correct that you cannot achieve aggregate throughput when presenting a single LUN through a single storage processor with a single IP address. However, if you switching infrastructure allows for Etherchannel (Cisco) or LACP, then you could balance two different LUNs over two different IP's and Storage processors by using "Route Based on IP Hash" and Etherchannel or LACP on the physical switches. For further information, you can look at the following excellent article by Scott Low:

Also, vSphere 4 now supports iSCSI multipathing by using two different VMkernel ports instead of just using NIC teaming. I hope this helps.

Don't forget to use the buttons on the side to award points if you found this useful (you'll get points too).

Regards,

Harley Stagner

[jmapt]

Thanks for that link!

I am using ESXi free version, not quite to the point of being able to pay for the fancier features like vMotion but oh how we would love to! If this install goes well then we may be able to make a case for it.

As to the multipathing, do you have a good link for a good description on it? I think that is where I was getting a little confused with redundancy and just having two nics splitting across two different switches and aggregating bandwidth and failover that way. Is it something else?

Thanks,

Josh

[dcoz]

jmapt,

Also have a look at this link. http://virtualgeek.typepad.com/virtual_geek/2009/09/a-multivendor-post-on-using-iscsi-with-vmware-vs...

Its a really informative post which might help.

Regards

DC