General xSan questions for a new setup

Question

So I'm looking to setup xSan. Had mainly one question. I know it's recommended that you have a secondary metadata controller server incase one goes down, but is this absolutely needed? We will have very few (like 3) people using the system so it won't be in use very often. If the controller goes down, does the system go down entirely, or can clients still access data with the potential of messing things up because the metadata server isn't functioning?
Thanks.

Answer 1

If you have one controller and the controller goes down, the SAN goes down and you run a higher risk of volume damage. The reason for a dedicated backup controller is so that when the primary goes south, there is another system to take of the SAN control, allowing you to complete writes and shut the volume down cleanly.
If the system is not going to be used that often, are you sure Xsan is the right solution for you? Even if you try and scrimp to save money and make a workstation a backup controller, you are still going to spend about $40K for the solution ($20K for a single RAID array, $7k for a dedicated controller, $4k for the FC switch (you should get two), wiring costs, redundant power, cooling, etc). That is a lot to spend for something that is not going to get much use.
Oh, and don't go easy on RAM. For your controllers get 2 Gigs per SAN volume and at try to leave 4 Gigs as overhead for the OS and other services. Don't run anything else on the main controller other than DNS and Dir Services (unless you are doing AD integration).
Hope this helps