Lustre discuss - Dec 2011 - Setting lustre directory and content immutable but keep permissions

For a policy issue with scratch space we want to lock a users scratch space that
lives on lustre 1.8.x.

We want users to be able to grab their data but not be able to add any more,
they also do not need to delete files.

We could recursively remove write bit, problem is we at time may wish to restore
write access to the files with the same permissions they had before so we wish
to not change the permissions.  We also don''t want to put the stress of
a bunch of chmod''s on the MDS.

So short is there a simple way to say ''directory and children not
mutable''  that is undoable by an admin?

Thanks!

Brock Palen
www.umich.edu/~brockp
Center for Advanced Computing
brockp at umich.edu
(734)936-1985

On 2011-12-14, at 2:54 PM, Brock Palen wrote:
> For a policy issue with scratch space we want to lock a users scratch space
that lives on lustre 1.8.x.
> 
> We want users to be able to grab their data but not be able to add any
more, they also do not need to delete files.
> 
> We could recursively remove write bit, problem is we at time may wish to
restore write access to the files with the same permissions they had before so
we wish to not change the permissions.  We also don''t want to put the
stress of a bunch of chmod''s on the MDS.
> 
> So short is there a simple way to say ''directory and children not
mutable''  that is undoable by an admin?
Mount the filesystem read-only on the clients...  Using:

client# mount -o remount,ro /mnt/lustre

will work on the mounted filesystems.  It needs to be done on all of the
clients, and the "ro" option could be put into the client /etc/fstab.

It is also possible to actually mark files immutable with:

client# chattr -R +I /mnt/lustre

which needs to be done on only a single client, but it needs to walk the
whole filesystem to do this.  You could alternately mount the filesystem
locally on the MDS and do it directly to the ext4 filesystem more quickly, but
it would take the filesystem offline.

Cheers, Andreas
--
Andreas Dilger 
Principal Engineer
Whamcloud, Inc.