[nSLUG] vmware for Linux virtualization on production servers

Ian Campbell ian at slu.ms
Thu Mar 12 23:25:51 ADT 2009

On Thu, Mar 12, 2009 at 10:28:51PM -0300, Hatem Nassrat wrote:
> > > Doesn't seem to have the benefits of journaling or this wouldn't be
> > > happening.
> > 
> > I'm not sure what "it" is in this context. If you're talking about
> > something like Workstation/Fusion/Server/Player then it will have the
> > benefits of whatever your underlying filesystem is. Journalling isn't
> > a magic bullet, if you kill the power and updates haven't been flushed
> > to disk, they get lost.
> There are a few silver bullets though. I have recently heard about ZFS,
> a filesystem that supports rollbacks and instant backups. 

Right, but it doesn't support "magic"

If the data hasn't been synced to disk then any sort of outage will
result in a loss thanks to write caching. You may have read about it
the other day in that EXT4 story on slashdot. What I was saying is
that this is true for all virtualization packages, not just VMware.
KVM is not immune from leaving things in a bad state if things are
stopped unexpectedly.

> What I dislike most about vmware, is that it is not open source, so
> whats free now may not be later. I will be trying out:
>     http://www.virtualbox.org/
> It seems cool and it supports an unlimited number snapshots per vm. It
> also runs on Linux, Solaris, OS X and Windows.

Nobody using this in a production environment is going to be doing it
without a support contract of some sort unless they're a glutton for
punishment, so free probably isn't a major concern. It shouldn't be,
at least.

VirtualBox is buggy, has poor USB support, and the snapshot system can
(amusingly for me, probably not amusingly for you) lose data.

Good luck.

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