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Re: [LUG] OpenVZ, anyone?

 

On Fri, 19 Feb 2010, Simon Waters wrote:

Gordon Henderson wrote:
Wondering if anyone here's run OpenVZ?
Nope but I had a virtual host that worked that way once.

Seemed to work okay.

Some of the memory management was "interesting". Running "varnish"
showed a few of the issues with memory, I think it doesn't handle memory
mapped files well in the client or some such. It ran Squid passably
instead, but varnish is a better reverse proxy.

I've used UML, it was fine except for lousy I/O performance in the
configuration we had. And it required bespoke kernels etc, so a lot of
messing around to get started and to upgrade kernels etc.

I think XEN is probably best supported virtualization on Debian.

kvm is up and coming.

I'm concerned about reliability of virtualization technologies. And as
such any that don't offer distinct benefits in this area (i.e. switching
hosts when one fails automatically) is likely to drop reliability of
performance. Any specific heavy lifting tasks may still show
deficiencies of virtualization.

Also try and use something you can run out of stock kernels unless you
really enjoy compiling your own kernels and the testing that comes with
that.
Well, I compile my own kernels as a matter of course, however OpenVZ 
applies 5MB of custom patches to it. There are "stock" kernels for Debian 
with it ready patched in though.
So, after some reading, it seems to be a better way to allow a program 
running in an OpenVZ container access to a shared timing source (used by 
Asterisk), rather than have each VM run it's own 1000Hz timer. (And they 
have specific entries in their wiki for asterisk too - always a bonus)
Migration isn't something I'm after right now, but does seem intersting - 
migrating an Asterisk instance is going to lose calls anyway, no matter 
what - Ethernet switches, ARP caches, etc. which you might get away with 
on a web server...
Xen was the other I've been looking at, but this "containerising" approach 
of OpenVZ is growing on me. Might be too busy this weekend to play though 
)-:
Cheers,

Gordon

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