Re: [Gluster-devel] RPM / BerkeleyDB on GlusterFS

[Gordan Bobic]

Brent A Nelson wrote:
> On Mon, 12 Jan 2009, Gordan Bobic wrote:
>
> > Brent A Nelson wrote:
> > > I believe you're looking for shared writable mmap support, which 
> > > requires a very recent (maybe) or painfully-patched FUSE; it's not 
> > > really up to GlusterFS (I think it will probably just work, if your 
> > > FUSE is somehow able to support it).
> >
> > I was actually more thinking about an option to rpm/bdb to make it no 
> > use mmap.
>
> I don't know for rpm; apt-get certainly did not have any such option, 
> although someone did create a patch to disable it in apt-get.

BDB seemingly has such options, but I haven't managed to get them to 
work. Putting the mmap disabling flag in /var/lib/rpm/DB_CONFIG did 
nothing. :(

> > > So, if you can't get shared writable mmap to work, try the workaround 
> > > with tmpfs or another filesystem (perhaps even an NFS mount of a 
> > > GlusterFS directory).
> >
> > Would that actually work? Exporting /var/lib/rpm via NFS and mounting 
> > it to fake some kind of mmap support? It's an inspired solution, I'll 
> > grant you that. I'll have to try it. :-)
>
> tmpfs certainly worked in my case, and others claimed that NFS in 
> general would work.

The with the tmpfs solution is that it requires extra work to keep the 
rpm DBs in sync. Not ideal.

> NFS to a filesystem that doesn't itself support 
> shared writable mmap (such as GlusterFS or any other FUSE filesystem)? 
> Well, we probably won't know for sure until you try it. ;-)

Well, I'm trying to get it working at the moment, but when I'm exporting 
it from glusterfs I get:

mountd: Cannot export /var/lib/rpm, possibly unsupported filesystem or 
fsid= required

I am using the fuse stuff from here:
http://ftp.gluster.com/pub/gluster/glusterfs/fuse/fuse-2.7.3-2.src.rpm

Am I missing something?

Gordan