I have come to the conclusion that SAN Booting VMWare ESX is just a bad idea in production. By production, I mean in an environment where you have at least two redundant paths to your storage, and the machines are intended for 24/7 up time.
I admit I am talking more about iSCSI than FC because I haven’t investigated FC as much. What do you think? I normally would post a bunch of links to support my theory and I will be happy to do so if there is interest (In other words, I can’t find them right now but I wanted to post this).
Why would you not want to SAN Boot ESX? Isn’t that the rage? Yes, yes it is.
If you SAN booted it, wouldn’t you be able to replicate the boot LUNs to another site and have all in one DR? Wouldn’t you get deduplication of the ESX LUN, snapshots, and all the other great things that make SANs the end all be all of storage? Yes, yes you would.
So, it you are gaining all these great advantages, why not do it? One simple reason, local fail over. From what I have seen and heard, ESX just really doesn’t have the multi-path code in place today to handle having the connection to the boot LUN ripped out from under it. I would think the FC is more robust but I haven’t tested it. If you are doing this and have tested it, please let me know!
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We have been booting VMware from SAN and do not want to do it differently. One important thing is to boot from NFS and use an N Series as your Storage Server. You therefore can use 1 GB or 10 GB adapters in your servers and also save on licensing because the FibreChannel protocol is not used on the N Series.
Sent me an email and I will sent you additional informaton.
Oh … and it makes using Open Fabric Manager much easier when you use boot from SAN … ehh NFS.
I would love to hear more about it! I will be in contact. Thank you very much!
I’ve heard more than once that ESX fabric driver doesnt compare to other drivers out there such as Linux Qlogic Multipathing. Thats its not a true multipath driver that it cant load balance thats its very touchy. I’ve seen some of it first hand but at times Id almost question the SAN setup when I’ve seen it. I saw your post on not using Fibre for ESX booting and Id like to know if you had any comments on the ESX driver and was to curious to your thoughts and of your readers.
Daniel - Thank you for your post. Sorry for the delay in posting the comment, I have been on vacation.
Here is what I have been told by other engineers in my company with more FC SAN boot experience than myself.
FC Boot is robust in the fact that the connections are redundant and if a path fails, the other will kick in and ESX will not crash (purple screen of death). But, it is not an active-active connection as you state.
iSCSI Boot does not handle losing a path and the machine will PSOD on you even if you have redundant connections. The drivers just do not handle it well.