I'm planning to move two separate vmware ESXi 4.0 hosts into a cluster to use the vMotion and HA capabilities of ESXi (essentials plus). Right now we have a dev vm host and a production vm host and want to be able to use the dev vm host as an HA host if the production vm fails. We use almost exclusively dell Servers in our shop.
I'm considering an Equal logic PS4000x SAN with 9.6 TB 10K drives or a PowerValut MD3000i or MD3200i series. I have a few questions. Which is a better solution for vmware hosts and adding storage? I'm getting mixed feedback from dell that we would need something more than a switch in between the SAN and the ESXi hosts to allow us to use the vMotion and HA capabilities. Is that true?
Which SAN options would allow us to grow the datastores and SAN storage the easiest in the future? We currently have a File server serving 2 TB and growing of data we would like to P2V. Are the Dell solutions a bad choice?
Should we go with NetApp hardware? Our budget is fairly flexible, not crazy, but the ability to easily and cost effectively add storage in the future is important.
Best Answer
I've recently implemented an EqualLogic PS4000XV, connected via 2 x Powerconnect 6224 switches to a pair of R710 ESXi hosts running off SD cards.
Performs very well for HA, vMotion etc. You can get MPIO working between the SAN and hosts fairly easily (just a bit of esxi remote cli futzing).
The only drawback of the PS4000XV that I've seen so far is the storage processor setup - You have a pair of SPs in the unit but only one is active at one time. The other one sits there with its ports offline. So you're losing some possible performance there, as you're talking via a max of 2 or 3 interfaces. If you fail-over to the other SP there's a time lag while it negotiates its ports and spins up. I'm assuming the higher spec PS units don't have this limitation and can provide an active/active SP configuration.
Dell's recommendation for the SAN is to configure it as a single RAID 50 array, so you end up with 6.2Tb usable.
Your expansion option with this model is basically 'buy another unit'. However you just plug it into the same storage fabric (switches), and it can all be managed through a single 'group' IP and console... so not much of a management overhead.
Regarding HA in VMWare - When you enable HA it only happens for a single VM... You don't tie two VMs together. The VM is spun up in lock-step across 2 hosts at once, and memory is synced between the hosts so that if one host fails, the other host instantly picks up the slack. So that method doesn't fit with 'use the dev VM as DR with HA'.
If you're planning to literally use your dev VM as a DR fail-over for the productin VM, Please think very carefully about the practicalities of that. Your DR configuration needs to be able to spin up as a production service with as little time-lag as possible (that's the whole point of DR), so how close to production is the dev box going to be at any one point in time?
EDIT To enable vMotion on ESX, you must ensure the CPUs running on your host servers are near-identical. If you run incompatible CPUs, you won't be able to vMotion/cluster/HA between the hosts. VMWare and vendors provide compatibility matrices to verify this: