VMware VSAN

I really like the new VMware VSAN technology. However, I can only think of one real use case.

 

VMware VSAN is a way to turn the commodity hard disks that sit inside your ESXi servers into a distributed storage array. It requires at least 1 SSD drive in each server, which it uses to increase the performance of the array.

 

It also requires a minimum of 3 hosts. This is where I start having problems with the product.

 

I have installed vSphere in many SMB’s and also large enterprise customers.

 

The SMB’s will typically purchase vSphere Essentials or Essentials Plus – it is a perfect fit for them. Provides them with enough capacity while being inexpensive enough to provide good value.

 

However, in order to make VSAN work, you really need 4 hosts or maybe 5.  I want N+2 redundancy for my clients, so I want to be able to take a host down (maintenance), and still be able to function. But then what if a host that is in production fails? So, I require that the system can handle a failure while a server is in maintenance.

For a SMB client with 3 servers, this isn’t going to work….VSAN will fail if it goes down to 1 server. But in a shared storage environment (and I sell a lot of the little EMC 3150 storage arrays), this would not be a problem.

And a SMB customer doesn’t want to purchase extra servers just so his VSAN can function – better to spend the money on a shared storage array that is dedicated for the purpose and has redundant service processors that handle failures, online updates etc.

 

For large enterprise customers, you just won’t be able to fit the storage requirements they have into servers. Many of these customers are purchasing blades (Cisco UCS is product that I install alot and love!) and you simply cannot fit a lot of storage inside these units.  In fact, I am now recommending just booting from either a) Auto Deploy server, or B) USB sticks (or a combination of both using the Stateless Caching feature of the Auto Deploy server.

 

So…where do I see this technology being useful?  In a VDI (Horizon View) deployment.  I would still see the customer using a SAN, but it makes sense to store the Replica’s (copies of the Golden Master images) on the VSAN for close and fast access.

 

This is just my opinion – let me know what you think.

 

Jim