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Filesystems

UPDATE 11/23/99

Home directory quotas have been increased to 500Mb.

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Disk space on the Origin2000 system is divided into the following filesystems:

Home Directory
--------------

   The /u filesystem contains all user home directories.  Each user has
   a 500 megabyte disk quota within the /u filesystem. Home directories
   from frey.ncsa.uiuc.edu are NFS mounted on all the other machines.
   The command "quota -v" gives disk usage and limits.

   The /u filesystem is backed up daily.

Scratch Directories
-------------------
   Each machine in the Origin array has a local XFS scratch filesystem.
   Each scratch filesystem is named /scratch-"machine name" (eg. 
   /scratch-modi4). Access to all batch machine scratch filesystems 
   from any other machine is read-only. 

   Interactive scratch: /scratch-modi4
   -----------------------------------

   The interactive scratch /scratch-modi4 is intended for short-term use,
   and should be considered volatile. No user disk quotas are in place
   at this time. However, no guarantees are made as to how much space will be
   available at any time. Also, files may be removed at any time should disk 
   space become critically low.

   The purge policy on files in /scratch-modi4 is based on the size and time 
   since last access:  
       
	File Size		Removed after
	> 25 Mbytes		1 day
	< 25 Mbytes		14 days
   
   Please do not attempt to circumvent this removal scheme, (e.g., with 
   touch).  Such attempts may result in the loss of access to the 
   scratch filesystems.  Users are responsible for saving their
   files to alternate storage, for example, the mass storage system,
   UniTree. (See unitree, mssftp, and msscmd man pages.)  

   Users are notified via email when files are purged. If you do not want 
   to receive email messages about purged files, enter the following command 
   at the shell prompt while logged on modi4:

                touch ~/.nopurgemail

   Please note that backups are NOT performed on the scratch directories.
   In the event of a disk crash, files on the scratch directories are
   unlikely to be recoverable. In the event of a file purge, files are NOT
   recoverable. Therefore, users should make sure to back up their files
   to permanent storage as often as significant changes are made, at least
   daily.


   Batch scratch filesystems
   -------------------------

   Each batch job has a per-job scratch directory that is created at the
   beginning of the job. This directory is created on the local scratch
   filesystem on the host where the job runs, and is based on the batch
   JobID and the start time of the job. The name of this directory is
   available to job scripts in the $SCR enviroment variable.

   See /usr/news/Batch_Scratch for details.

   The purge policy in the batch scratch filesystems ($SCR) is 
   as follows: 

   For jobs using the msscmd -b/-B option, after job completion, files 
   are not purged from the $SCR filesystem until they are successfully 
   transferred or it has been determined that the transfer will never 
   happen (e.g., due to user syntax error). For jobs that do not use the 
   msscmd -b/-B option, the $SCR directory will be purged 2 hours after job 
   completion until November 22, 1999, and immediately after job 
   completion starting November 22, 1999. For this reason, the user must 
   make sure to save all needed files within the batch job.

   For jobs using the msscmd -b/-B option, email is sent to the user once 
   the transfer requests to mass storage are processed by the system. Users 
   are not notified in email when files are purged from the $SCR directory. 

Reserved Scratch Directories
----------------------------

   A reservation based scratch directory (/scratch-res4) is available 
   for users that require more space for a period of time. This space is 
   not purged like the regular scratch directories, however, they are 
   *not* backed up. Users are responsible for saving their files to permanent
   storage, for example, UniTree.  

   Information on requesting space on these filesystems is contained in the 
   file /usr/news/Reserved_Scratch.

/tmp and /usr/tmp Directories
-----------------------------
   The /tmp and /usr/tmp directories are intended for temporary files that
   are used during the execution of a process or job.  Please do not use
   more than 10 Mbytes of disk space in these directories since there is
   limited space.  Do not attempt to use these directories for permanent
   storage.  Files placed in /tmp or /usr/tmp may be purged at any time.
Silicon Graphics Origin2000:usr/news/Filesystems
Last Modified: July 21, 2003