I would not use sparse images but _ONLY_ for testing purposes. Using
sparse files is not recommended due to data integrity and performance
issues (degradation up to 3x) but not in a production environment.

-- Robin



On Tue, Apr 8, 2008 at 9:16 PM, Dave Costakos <david.costakos@(protected):
>
>
> Sorry, I haven't replied to my thread, but I've been traveling :-).
>
> I see this same problem using 5.2 beta on x86_64 dom0 with 32-bit and 64-bit domU guests.
>
> For what it's worth, I have 100+ guests with Sparse images and once they are imaged, they seem to perform just fine to me and seem to save 40-80% of the disk space compared with nonsparse images. So, I see a clear value in using sparse files and having them work. Moreover, for those of use who don't use GUIs, sparse images are the default for the 'virt-install' tool from RHEL.
>
> Now, one thing I have noticed is that the slow formatting only seems to occur duing the install process. If I attach a 2nd sparse disk to my VM after the install and run mkfs on it, it seems to me to perform comparably to physical hardware. I just now attached a 150 GB sparse file to a running VM and made a file system on it in less than 2 minutes. So, at least for me, the problem seems confied to the anaconda install.
>
> -Dave.
>
>
>
>
>
> On 4/8/08, Coe, Colin C. (Unix Engineer) <Colin.Coe@(protected):
> >
> > IIRC the 5.2 BETA notes said something about disk IO in general
> > regarding Xen guests being improved.
> >
> > CC
> >
> > > -----Original Message-----
> > > From: rhelv5-list-bounces@(protected)
> > > [mailto:rhelv5-list-bounces@(protected)
> > > Sent: Tuesday, 8 April 2008 6:05 PM
> > > To: Red Hat Enterprise Linux 5 (Tikanga) discussion mailing-list
> > > Subject: Re: [rhelv5-list] Xen Guest Disk Formatting Unfeasibly Slow
> > >
> > > Zavodsky, Daniel (GE Money) wrote:
> > > >   Well you are not doing this in the guest but in Dom0... If you
> > >
> > > That's true; my xen system's waiting for someone to fix its kernel:-(
> > >
> > > I'll go and sulk in the corner:-)
> > >
> > > It shouldn't be slow; has anyone tried it with kvm?
> > >
> > >
> > >
> > >
> > >
> > > --
> > >
> > > Cheers
> > > John
> > >
> > > -- spambait
> > > 1aaaaaaa@(protected)
> > > -- Advice
> > > http://webfoot.com/advice/email.top.php
> > > http://www.catb.org/~esr/faqs/smart-questions.html
> > > http://support.microsoft.com/kb/555375
> > >
> > > You cannot reply off-list:-)
> > >
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>
>
>
>
>
> --
> Dave Costakos
> mailto:david.costakos@(protected)
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