> ----- Original Message -----
> > From: "M. Mohan Kumar" <mo...@in.ibm.com>
> > To: vdsm-devel@lists.fedorahosted.org
> > Sent: Wednesday, July 25, 2012 1:26:15 PM
> > Subject: [vdsm] [RFC] GlusterFS domain specific changes
> >
> >
> > We are developing a GlusterFS server translator to export block devices
> > as regular files to the client. Using block devices to serve VM images
> > gives performance improvements, since it avoids some file system
> > bottlenecks in the host kernel. Goal is to use one block device(ie file
> > at the client side) per VM image and feed this file to QEMU to get the
> > performance improvements. QEMU will talk to glusterfs server directly
> > using libgfapi.
> >
> > Currently we support only exporting Volume groups and Logical
> > Volumes. Logical volumes are exported as regular files to the client.
> >
> > In GlusterFS terminology a volume capable of exporting block devices is
> > created by specifying the 'Volume Group' (ie VG in Logical Volume
> > management). Block Device translator(BD xlator) exports this volume
> > group as a directory and LVs under it as regular files. In the gluster
> > mount point creating a file results in creating a logical volume,
> > removing a file results in removing logical volume etc.
> >
> > When a GlusterFS volume enabled with BD xlator is used, directory
> > creation in that gluster mount path is not supported because directory
> > maps to Volume groups in BD xlator. But it could be an issue in VDSM
> > environment when a new VDSM volume is created for GlusterFS domain, VDSM
> > mounts the storage domain and creates directories under that and create
> > files for vm image and other uses (like meta data).
> >
> > Is it possible to modify this behavior in VDSM to use flat structure
> > instead of creating directories and VM images and other files underneath
> > it? ie for GlusterFS domain with BD xlator VDSM will not create any
> > directory and only creates all required files under the mount point
> > directory itself.

Thanks Federico.
> From your description I think that the GlusterFS for block devices is
> actually more similar to what happens with the regular block domains.
> You should probably need to mount the share somewhere in the system and
> then use symlinks to point to the volumes.
> Create a regular block domain and look inside /rhev/data-center/mnt/blockSD,
> you'll probably get the idea of what I mean.
GlusterFS with BD xlator will be a hybrid of block and posix fs
domains. I will try to post more information about this model.

vdsm-devel mailing list

Reply via email to