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Saturday
Mar152008

Virtualization Risk and the Fishtank

I missed this article in CIO (Top Ten Virtualization Risks Hiding in Your Company) when it was published about a month ago. After running through a believable list, I looked at one of the comments and couldn't help but smile:



... I think the comments above missed risk #11, the physical world outside any hypervisor host.

All hypervisors still depend on underlying physical machines being correctly connected to network and storage -- in multiple paths, to allow access for all VMs correctly.

In other words, all the above article comments apply to moving around the virtual machine "fish" inside the hypervisor OS "fishtank" -- but who moves and manages the associated fishtanks (with associated network & storage I/O plumbing etc)?



Kevin Epstein (of Scalent) then goes on to set out a number of additional problems, and although he makes sure to inform the reader that (in his opinion) Scalent solves these problems, I have to agree with the problem identification (if not completely with his solution):



1. Network connectivity matters

All hypervisor hosts in a group or "cluster" who are going to share virtual machines -must- share a LAN subnet.

2. Storage access matters

All hypervisor hosts in a group or "cluster" who are going to share virtual machines -must- share storage access.

3. Hardware failover must be anticipated

VMs will fail to another clustered hypervisor... if, and only if, one exists and has cycles! (See point 1 and 2)

4. Movement between Physical and Virtual (and back, repeatedly) is a necessity in real data centers, and is -not- usually seamless ...

5. Non-x86 Hardware

Not all hardware is x86! Sun now has LDOMs, AIX too, how to manage workloads between those and the rest of the virtual universe?

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