Using /tmp and /scratch

Why?  The disk that contains the home directories is not actually mounted on any of our machines.  So, every access to a file in your home directory must go over the network.  For this reason, any program that has a lot of I/O should be run in each machines' local /tmp directory --- otherwise the network will be flooded and the program will slow by a factor of possibly 100.

Note that the /tmp directories are not backed up.  Any data that you want to have backed up should be moved to your home directory.  Files in a /tmp directory will be automatically deleted 100 days after their last access.

Scratch space
The scratch disks are for storage of large amounts of data.  The scratch disks are not automatically cleaned, but they are mirrored to another set of disks for disaster recovery (that you won’t have access to).  Access to the scratch disks is via the network, so do not run programs from a scratch disk. Instead, run in a /tmp directory as described above and transfer the data later (scripts can be handy for this). Data placed on the scratch disks will stay there indefinitely.  After you are done with a set of calculations, you should clean your scratch directories to make sure you’re keeping only the critical information. You should also compress any files left there.

The scratch disks are available via the /scratch directories:

Esry Group
Directory name	Size
/scratch1	200 Gb
/scratch2	200 Gb
/scratch3	200 Gb
/scratch4	200 Gb
/scratch5	500 Gb
/scratch6	200 Gb
/scratch/enlil	400 Gb
/scratch/fuxi	400 Gb
/scratch/juya	400 Gb
/scratch/odin	400 Gb
/scratch/wukong	400 Gb
/scratch/ixion	400 Gb
/scratch/titan	1500 Gb
TOTAL	4200 Gb

To use the /tmp and /scratch directories:

1. Change to the directory you wish to use.
2. Make a directory named for your userid.
3. Work in this new directory.
   

This page last updated Nov. 2009.