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Re: Grizzly release notes and the never-ending image-cache-manager issue


On Thu, Apr 4, 2013 at 4:45 PM, Michael Still <mikal@xxxxxxxxxxx> wrote:

> On Fri, Apr 5, 2013 at 7:20 AM, Lorin Hochstein
> <lorin@xxxxxxxxxxxxxxxxxx> wrote:
> > Michael (et al):
> >
> > The Grizzly release notes
> > <https://wiki.openstack.org/wiki/ReleaseNotes/Grizzly> say:
> >
> > "The image-cache-manager has been turned on by default. This may have
> > potential issues for users who are using a shared filesystem for their
> > instances_path. Set remove_unused_base_images=false in your nova.conf
> file
> > on your compute nodes to revert this behaviour."
> >
> > My understanding was that in Grizzly, this wasn't an issue since shared
> > storage was automatically detected (e.g.
> > https://bugs.launchpad.net/nova/+bug/1075018)
> This is my understanding as well -- that we now detect shared storage
> and do the right thing. I don't have any data on how much real world
> testing that code has experienced though.
> > Is it safe to zap this from the release notes?
> Safe is a relative thing. I'd be more comfortable if I knew that
> someone had deployed the code and had a good experience, but when I
> ask on the operators list I get puzzled stares...
> Michael

I reworded the release note as follows:

Grizzly should now be able to detect when a shared filesystem is being used
for instances path, eliminating a bug in previous versions where the image
cache manager erroneously deleted images that were in use on shared
filesystems. However, this bugfix has not been extensively tested in
production environments. If you wish to be conservative, you may set
image_cache_manager_interval=0 in your nova.conf file on your compute nodes
to prevent the image cache manager from deleting any images.

Lorin Hochstein
Lead Architect - Cloud Services
Nimbis Services, Inc.