[gpfsug-discuss] mmchfs -k nfs4 impacts?

Helge Hauglin helge.hauglin at usit.uio.no
Tue Aug 30 11:02:26 BST 2022

Hi Stephen.

> Also I didn't mention that we also need NFSv4 access and
> native GPFS, this will not be SMB-only. It will actually be mostly
> GPFS native.

Beware that when writing via SMB, samba default permissions will be applied
to new files and folders, which might not give the permissions your
users need.

On our CES clusters, the samba default permission is 0755 / 0744 [1].
We want either 0770 or 0775 by default.  This we get by setting these
permissions in NFSv4 ACLs in relevant folders, plus turn on inheritance
for the ACEs to new files and folders.  The side effect of having NFSv4
ACLs with inheritance is that 'umask' in processes writing via GPFS or
NFS is ignored.  I have not tried. but I guees it works similarly with


| # testparm  -s -v | grep mask
| Load smb config files from /var/mmfs/ces/smb.conf
| [...]
|         create mask = 0744
|         directory mask = 0755

> I don't think existing ACLs will be adversely
> affected. In a test filesystem with "-k all" I set some POSIX ACLs and
> converted the filesystem to "-k nfs4" and the result looked
> reasonable.  Plus I ran mmgetacl -k nfs4 on numerous files/dirs with
> POSIX ACLs in our production filesystem and the results looked
> promising.

I would recommend standardizing on one type of ACLs, which will give you
less variants to deal with, simplifying administration.


Helge Hauglin

Mr. Helge Hauglin, Senior Engineer
System administrator
Center for Information Technology, University of Oslo, Norway

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