[CentOS] OT: Why VM?
Devin Reade
gdr at gno.org
Fri May 27 21:29:19 UTC 2011
But taking the other side of the argument, here are two scenarios where
I *wouldn't* use virtualization (one could certainly enumerate more):
1. A production DB server or server cluster.
2. I've had services where I needed to maximize uptime. One option
I tried were VMs and being able to move the VM back and forth
between hosts. That might cover hardware failure, but I'd still
take outages when I needed to upgrade software in the VM. Moving
to a traditional HA solution on physical hardware means the outages
are now measured in seconds instead of minutes, and most of the time
are undetectable by the users.
I also tried services where the HA nodes are themselves VMs, but
was less than impressed with operational stability.
When CentOS 6 comes out, though, I'll be interested to see how (2)
behaves when it comes time to do a rolling upgrade from CentOS 5
(bring a node down, install and reconfigure C6 from scratch, rejoin
the cluster, have C6 take over the services, then upgrade the other
node).
Thank god for test environments. And backups.
Devin
More information about the CentOS
mailing list