[lustre-devel] Fwd: llmount.sh does not use fs-specific paths to the ost(s) and mds it mounts

[Dilger, Andreas <andreas.dilger@intel.com>]

On 2016/05/10, 08:14, "Quentin BOUGET" <quentin.bouget.ocre@cea.fr> wrote:
>
>Hello!
>
>While trying to mount two different lustre filesystems on a local node
>with the "llmount.sh" script, I noticed that the path to mount mds and
>ost(s) was computed like this:
>
>eval mntpt=${!var:-${MOUNT%/*}/$facet} # var is not defined by default,
>so this removes
>                                                                     #
>everything after the last '/' of $MOUNT
>
>
>The code can be found at test-framework.sh in the function "facet_mntpt"
>around the line 3226.
>
>
>By default MOUNT is initialized like this:
>
>MOUNT=${MOUNT:-/mnt/${FSNAME}} # default: "/mnt/lustre"
>
>
>Thus the default mountpoints for mds and ost(s) are "/mnt/mds1" and
>"/mnt/ost1".
>Because of that, when trying to do two successive calls to "llmount.sh"
>with two different values for FSNAME, the second fs to be mounted will
>unmount the first's mds and ost(s) (paths are identical).
>
>
>Is there any reason to truncate the MOUNT variable like this ? Shouldn't
>the mountpoint path look more like "/mnt/<fsname>-mds1" and
>"/mnt/<fsname>-ost1"?

I don't think there is any particular reason it was implemented this way,
just that it has worked for many years without the need to include the
fsname into the MDT/OST mount points... :-)

If you want to expand it to allow exporting multiple filesystems from the
same MDS/OSS nodes then your suggestion to use $FSNAME-$facet in
facet_mntpt() is reasonable.  Please submit a patch to verify this is
working correctly.  There may be some places in the tests that aren't
using facet_mntpt() yet.

Cheers, Andreas
-- 
Andreas Dilger

Lustre Principal Architect
Intel High Performance Data Division