[CentOS] Vitualization and Partitioning

Tue Sep 13 05:01:16 UTC 2011
Trey Dockendorf <treydock at gmail.com>

On Mon, Sep 12, 2011 at 6:52 PM, Thomas Dukes <tdukes at sc.rr.com> wrote:

>
>
> > -----Original Message-----
> > From: centos-bounces at centos.org
> > [mailto:centos-bounces at centos.org] On Behalf Of ken
> > Sent: Monday, September 12, 2011 12:36 AM
> > To: CentOS mailing list
> > Subject: Re: [CentOS] Vitualization and Partitioning
> >
> > On 09/11/2011 11:10 PM Emmanuel Noobadmin wrote:
> > > Hi,
> > >
> > >> When I do the install, do I or should I setup a separate partition
> > >> for guest
> > > That would be better from a performance point of view
> > >
> > >> OS's? From the redhat docs, it looks like the guest OS's reside at
> > >> /var/lib/libvirt/images/.
> > > This should be using files as disk files, which I did and
> > found it to
> > > be a problem when there is heavy I/O.
> >
> > I like LVM (for the reasons you cite).  Would you (anyone?)
> > say it's best to have one LV per guest or one LV for all guests?
> >
> >
> > tnx.
>
> I'm new to this but I would think you would want a separate LV for each
> guest. Seems I read somewhere, that you need one core per guest as well.
> That's why I'm opting for the Xeon processor rather than the iCore(x). Four
> cores v. two. More options.
>
> Can't believe this thread hasn't stirred more response. Maybe we all are in
> the learning phase.
>
> Eddie
>
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An LV per guest isn't necessary, but has its benefits.  What I did on one of
my server was a use two drives in RAID 1 for the system and then a RAID 6
array for the VM storage.  I've opted to use QCow2 images for the virtual
disks, so they all go on a LV I created "/vmstore" where all virtual disks
go.  I always try to keep the system paritions (/ and /boot) separate from
the data (with virtual server, I use /vmstore , or /var/lib/libvirt/images)
at least logically, if not physically.  My biggest consideration between LVM
and image files for the VM disks was snapshot capabilities.  While LVM can
do snapshots using lvm's native tools, it still requires extra steps to get
the VM's memory (if still running).  That considered I saw no benefit in my
case to use LVM when some other tools could combine the ability to do both
qcow2 and memory snapshotting at once.  Plus in my environment it is easier
to work with a single virtual disk file than deal with LVMs.
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