[Discuss] Redundant array of inexpensive servers: clustering?

[kentborg at borg.org (Kent Borg)]

On 03/30/2014 05:51 PM, Richard Pieri wrote:
> A more detailed plan for the basic Xen + checkpoint + DRBD 
> configuration I described.

I played with Xen back when, but I didn't like the too-tight coupling 
between the host and guest OSs. I forget what burned me but I upgraded 
something (the host?) and the guest quit working. Admittedly, this was a 
long time ago, things might have gotten better since, but 
para-virtualization isn't as flexible as complete virtualization. And 
originally my idea was for a bunch of archaic MS Windows servers--I 
don't think old MS Windows can run under Xen.

> It also has the same flaw: split brain. 

Split brain is a problem, but in my case I was looking for something 
that fit a single-rack, or now just in my house. In both cases I am 
assuming the ethernet cable between the two different boxes is one of 
the most reliable parts of the whole rig. Heck, I hadn't even gotten to 
automatic failover. A big win was no longer having a single point of 
"Nyah-nyah, it will take you *weeks* to get back up and 
running!"-failure that I was trying to fix in the original MS Windows 
server setup.

For basement server playing a thousand dollars buys a pretty capable 
collection of toys. Too bad time in the dearer resource.

> There's no quorum, and you can't get a quorum with DRBD. 

There is a non-free DRBD that handles more than two nodes. There might 
be something useful down that path.

-kb