[gpfsug-discuss] fast ACL alter solution

[Jonathan Buzzard]

On 28/07/15 17:28, Martin Gasthuber wrote:
> Hi,
>
> since a few months we're running a new infrastructure, with the core
> built on GPFS (4.1.0.8), for 'light source - X-Rays' experiments
> local at the site. The system is used for the data acquisition chain,
> data analysis, data exports and archive. Right now we got new
> detector types (homebuilt, experimental) generating millions of small
> files - the last run produced ~9 million files at 64 to 128K in size
> ;-). In our setup, the files gets copied to a (user accessible) GPFS
> instance which controls the access by NFSv4 ACLs (only !) and from
> time to time, we had to modify these ACLs (add/remove user/group
> etc.). Doing a (non policy-run based) simple approach, changing 9
> million files requires ~200 hours to run - which we consider not
> really a good option. Running mmgetacl/mmputacl whithin a policy-run
> will clearly speed that up - but the biggest time consuming
> operations are the get and put ACL ops. Is anybody aware of any
> faster ACL access operation (whithin the policy-run) - or even a
> 'mod-acl' operation ?
>

In the past IBM have said that their expectations are that the ACL's are 
set via Windows on remote workstations and not from the command line on 
the GPFS servers themselves!!!

Crazy I know. There really needs to be a mm version of the NFSv4 
setfacl/nfs4_getfacl commands that ideally makes use of the fast inode 
traversal features to make things better. In the past I wrote some C 
code that set specific ACL's on files. This however was to deal with 
migrating files onto a system and needed to set initial ACL's and didn't 
make use of the fast traversal features and is completely unpolished.

A good starting point would probably be the FreeBSD setfacl/getfacl 
tools, that at least was my plan but I have never gotten around to it.

JAB.

-- 
Jonathan A. Buzzard                 Email: jonathan (at) buzzard.me.uk
Fife, United Kingdom.