Today my fellow vExpert Erik Bussink opens a brand new site called vsan.info (He currently blogs at http://www.bussink.ch/. No prize for guessing its all about VMware’s VSAN technology, but with a particular twist – its focused on homelabbers. I’ve been chatting backwards and fowards with Eric over the last couple of weeks pumping him for information about homelabs generally, because its my intention to quit the colocation and go back to a homelab. I’ve been impressed with Eric’s works with the Shuttle format, and also his use of 2nd-hand InfiniBand kit to get a cost effective 10gb solution into his rig. I love this stuff as it takes me back to my days of running two Dell PowerEdge Pentium III with DEC JBOD to provide shared storage to two VMware ESX 2.x boxes (Sorry, I have to mention this because I believe I’m the only person to run VMware on Pentium III kit with JBOD as shared-storage in 2004!)
Anyway, less of my self-trumpeting (that sounds a bit icky doesn’t it?) back to VSAN. Why is Eric site SO important and SO necessary. A couple of reasons firstly – in production there will be budget to acquire the hardware to build VSAN using components from the HCL. VSAN is going to be massively more cost-effective than any commercial storage array, and by design comes ready built with redundancy and resiliency. The fact that you won’t be able to put “laptop style” SSDs in the system and get support won’t amount to hill of beans in this crazy world. The cost saving will be so massive they will be easy to justify to the bean counters. The same goes for the disk controller types. VSAN requires a support storage controller which has “pass-through” capabilities. That means the disks are present to the host as RAW, unformatted – without even a RAID level. If you can call this a JBOD type of configuration if you like. At the moment the listed of support storage controllers in the beta program is modest, and its clearly in VMware’s own interest to get as wide range of supported devices as possible. BUT, I think this is highly unlikely to include the sort of controllers found typically in a homelab “server” for reason which I hope are obvious.
To me that means homelabbers wanting to learn or use VSAN in their environments face two distinct challenges.
- Finding “good” SSDs that are cheap, offer the right amount of capacity and have a low failure rate (something the retail SSD market doesn’t have a terrific reputation for as you probably know). This is something that Vladan Seget recently wrote about on his blog – http://www.vladan.fr/homelab-thoughts-vsan/
- Finding a controller that VMware ESX even recognises natively AND also supports a JBOD/Pass-Through mode.
For a while I’ve been verbally suggesting we should have a “Community HCL” for VSAN. One already exists for servers, motherboards and so on…
[Allow to be honest I think its massively out of date, and woefully underpopulated with devices… Just sayin’)
I’ve been looking closely at the HP ML350e series towers. They have massive expansion capabilities (up to a max of 196GB RAM) and have the space to allow for the adding of additional NICs and Disks. However, the onboard RAID controller card is NOT properly recognised by VMware ESX 5.5. It seems to present itself as generic SATA controller, which means it doesn’t support RAID. It means the disks have to be presented in JBOD style. That’s precisely what VSAN requires. The worry is if the controller isn’t properly detected and disappears in subsequent ESX updates I could be left with a truckload of HDD/SDD that I can’t address. In the past the fact that local disk controller wasn’t recognised wasn’t a biggy. Folks either replaced the card or just used USB/SD-card too boot with the VMs on cheapo NAS. Now with the on-set of VSAN that local controller is becoming MUCH more important than it ever was in the past. That’s why I support whole heartedly Erik’s initiative. Go VMware Community, Go!