US Atlas NFS Service at the RACF
NFS is one of the means though which working space is made available to US Atlas users. The NFS storage space comes in two flavors, backed up and un-backed up. The former is predominantly the user home directories, although there are a few exceptions. The later constitutes the bulk of the available NFS storage. Specific US Atlas working groups have dedicated storage space, submit a trouble ticket to request access to working group storage space. General user scratch space is available in /usatlas/scratch.
User scratch space is provided in /usatlas/scratch. This file system is considered to be temporary space. Old, large files in this location may be deleted without warning if free space becomes critically low. A cronjob running every night checks the available free space and, if necessary, automatically removes large files that have not been accessed in a few months. Please use one of the other areas if you need a more permanent storage location.
The cleanup script operates based on four thresholds:
- File Age:
- The script will only consider files for removal that are older than this threshold, currently set to 30 days (access time).
- File Size:
- The script will only consider files for removal that have a size greater than this threshold, currently set to 10Mbytes.
- High Watermark:
- The script will only look for files to remove if the total disk usage goes above this percentage, currently set to 90%.
- Low Watermark:
- The script creates an array, indexed by age in days, with the total size of all files of the same age. It then finds the appropriate age threshold to remove the oldest of the above found files that will result in the total disk usage going below this threshold, currently set to 70%.
Table of All US Atlas NFS file systems.
The following is a table of the NFS file systems that are available
for use by US Atlas users. With the exception of /usatlas/u (users home
directories) ALL file systems are NOT backed up. For file
systems with quotas enabled, quota information can be queried on the US
Atlas Linux Farm nodes by running the quota
command. For access to space in the /usatlas/groups/* sub directories,
submit a Trouble Ticket with your username and the
directory in which you would like space.