[monolith-users] Efficient usage of Monolith file systems.

[Torgny Faxen]

Dear Monolith user,
a contributing cause to the slow response of the Monolith system is the frequent user job usage
of global file systems for scratch files.

The Monolith system has two levels of file systems:

- a local file system that is directly attached to each compute node, called /disk/local.
- global file systems mounted through NFS, called /disk/global and /home.

Performance for the global NFS mounted file systems is much less than for the local file system
and if too heavily used also impacts overall system performance (which we are sure you all have
noticed over the last weeks).

So, in order to improve the situation we urge you to please use /disk/local for local files.
This will improve the performance of your job and relieve the system.

The rules for the /disk/local file system are simple:
- 20 GB is always available for each job.
- After the job is completed, the file system is cleaned so you need to copy
   data you like to save before the end of the job.
- It is a purely local filesystem and can not be accessed from other nodes.

In addition, we have modified the G98 execution scripts setting the environment
variable  "GAUSS_SCRDIR" to /disk/local. This means that G98 jobs are now forced to use /disk/local
for scratch files. (Gau-xxx.rwf, Gau-xxx.scr, Gau-xxx.int, Gau-xxx.d2e and Gau-xxx.inp).

If you have any questions, please submit them to support at nsc.liu.se.


--
----------------------------------------------------------
   Torgny Faxén
   National Supercomputer Center
   Linköping University
   S-581 83 Linköping
   Sweden

   Email:faxen at nsc.liu.se
   Telephone: +46 13 285798 (office) +46 13 282535  (fax)
   http://www.nsc.liu.se
------------------------------------------------------------