Whether to use SAN or local storage for best High Availability for Esxi environment
Posted on 2014-03-13
I should probably lead into this by saying that this is my first production virtual systems rollout, so I appreciate your feedback and patience. I am configuring a virtual environment for a client that is currently running all physical hosts. It is a small firm, c. 15 users total, but the owner is very tech-oriented and forward thinking. Currently they are working off the following physical hosts:
1) Exchange 2003 server + DC
2) SQL Std 2005 server + file server
3) anti-spam server SMTP gateway
4) 2X server (similar to Citrix)
I am looking to condense these into 2 Esxi hosts that will be running the above server functions in an HA environment, along with an APC VMA server on each host that will generate an auto-shutdown in the event of power failure. So there will be 8 VM's in all. I plan to have 4 VM's operational on one host and 4 on the other host to split the regular workload, and in case of a host failure all running VM's (except the APC) will migrate to the remaining host. We'll be using either FT or HA to ensure either zero or minimal loss of uptime for all VM's across the hosts.
My question is one of architecture and reliability. One option I'm looking at is having 2 hosts with 96 GB of RAM and Esxi on SD media, and a Dell MD3220 SAN for shared storage, housing all VM's, data drives, etc. The second option is to equip both hosts with local storage, and setup the same failover scheme across both hosts. With the current configuration, price is c. 52K for the SAN + diskless hosts, and c. 44K for the 2 hosts w/local storage.
For this type of setup, is there a prevailing recommendation across industry pros on whether to SAN or not to SAN? I've read in a number of tech forums that some storage veterans recommend local storage vs. a SAN since it's a single point of failure and adds too much to the budget, Definitely no small difference in price as per above. However I've also read accounts of SAN's that run for years without ever power cycling them.
Many thanks for your opinions and thoughts,