[gpfsug-discuss] default owner and group for POSIX ACLs

[Jonathan Buzzard]

On 15/10/2019 17:15, Paul Ward wrote:

[SNIP]

>> ...I am not sure why you need POSIX ACL's if you are running Linux...
>  From what I have recently read...
> https://www.ibm.com/support/knowledgecenter/en/STXKQY_4.2.0/com.ibm.spectrum.scale.v4r2.adm.doc/bl1adm_admnfsaclg.htm
> "Linux does not allow a file system to be NFS V4 exported unless it supports POSIX ACLs."
> 

Only if you are using the inbuilt kernel NFS server, which IMHO is awful 
from a management perspective. That is you have zero visibility into 
what the hell it is doing when it all goes pear shaped unless you break 
out dtrace. I am not sure that using  dtrace on a production service to 
find out what is going on is "best practice". It also in my experience 
stops you cleanly shutting down most of the time. The sooner it gets 
removed from the kernel the better IMHO.

If you are using protocol nodes which is the only supported option as 
far as I am aware then that does not apply. I would imagined if you are 
rolling your own Ganesha NFS server it won't matter either.

Checking the code of the FSAL in Ganesha shows functions for converting 
between GPFS ACL's and the ACL format as used by Ganesha. My 
understanding was one of the drivers for using Ganesha as an NFS server 
with GPFS was you can write a FSAL to do just that, in the same way as 
on Samba you load the vfs_gpfs module, unless you are into self 
flagellation I guess.


JAB.

-- 
Jonathan A. Buzzard                         Tel: +44141-5483420
HPC System Administrator, ARCHIE-WeSt.
University of Strathclyde, John Anderson Building, Glasgow. G4 0NG