Open Stack

On Wed, Mar 13, 2013 at 5:12 PM, Michael Still <mikal at stillhq.com> wrote:

> On Wed, Mar 13, 2013 at 4:42 PM, Joe Topjian <joe.topjian at cybera.ca>
> wrote:
> > It would, yes, but I think your caveat trumps that idea. Having x nodes
> be
> > able to work with a shared _base directory is great for saving space and
> > centrally using images. As an example, one of my OpenStack's _base
> directory
> > is 650gb in size. It's currently shared via NFS. If it was not shared or
> > used a _base_$host scheme, that would be 650gb per compute node. 10 nodes
> > and you're already at 6.5TB.
>
> Is that _base directory so large because its never been cleaned up
> though? What sort of maintenance are you performing on it?
>

It's true that I haven't done any maintenance to _base. From my
estimations, a cleanup wouldn't reclaim a substantial amount of space to
warrant me doing an actual cleanup (basically "benefits of disk space
reclaimed" is not greater than "risk of accidentally corrupting x users
instances" yet).


> (As a side note here, I'd be interested in knowing what your largest
> images are in glance. I know that windows images can be quite large,
> but 650gb is still pretty huge).
>

I don't think it's terribly large. It's definitely going to get larger as
time goes on and I will definitely have to look at cleaning it up
eventually. Snapshot images that are no longer exist will be the biggest
offenders of unneeded _base disk usage.

The largest images do come from Windows. I have quite a few users using
many versions of Windows: 2008, 7, 2012. Some of those users take snapshots
of those images which duplicate the size.


>
> Note that the _base directory could be on local disk. I agree its
> still repeated storage, but it doesn't have to be an expensive filer
> or something like that.
>

I agree that _base sounds like a silly thing to put on an expensive filer.
In my case, though, that expensive filer is doing wonders each night when
it runs deduplication. The disk savings of Windows images + snapshots alone
is great. Linux images and snapshots also have great dedup results -- I
only pick on Windows due to the large size.


>
> Michael
>



-- 
Joe Topjian
Systems Administrator
Cybera Inc.

www.cybera.ca

Cybera is a not-for-profit organization that works to spur and support
innovation, for the economic benefit of Alberta, through the use
of cyberinfrastructure.
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