Home Filesystem /home
The emphasis of the /home filesystem is reliability over performance. All home directories are backed up to the CSCS archive nightly and no cleaning policy is applied.
Please, keep in mind that you are not supposed to exceed the 10GB quota which is enforced on your $HOME.
To check your usage type quota, which is a link to the following command:
/usr/local/bin/quota.ksh
If this command is not available on the platform your are working on, please email to help@cscs.ch.
Users are NOT supposed to run jobs from this filesystem because of the low performance.
GPFS Snapshots
Snapshots provide an online backup that allows easy recovery from common problems such as accidental deletion of a file, or need to compare older versions of the same file.
Snapshots of the entire GPFS file systems /users are taken every night at 03:00 AM. Snapshots of a file system are read-only; changes can only be made to the active (that is, normal, non-snapshot) files and directories. Only last three days snapshots are available. Older snapshots are deleted automatically.
How to restore a file from GPFS snapshots
GPFS snapshot creates a .snapshots subdirectory to ALL directories in the GPFS file system.
The .snapshots directories are invisible in the sense that the ls command or readdir() function does not return .snapshots. This is to prevent recursive file system utilities such as find or tar from entering into the snapshot tree for each directory they process.
For example, ls -a /users/<username> does not show .snapshots, but ls /users/<username>/.snapshots and cd /users/<username>/.snapshots do.
# ls /users/<username>/.snapshots
. .. snap-20100808 snap-20100809 snap-20100810
To restore a file or a directory from GPFS snapshots is EASY: type cd /users/<username>/.snapshots and choose the most convenient snapshot among the three available and copy the old file to your original directory.
Example:
fileA in the directory /users/<username>/dirA/ has been deleted or modified and you want to retrieve one of the older version.
# cd /users/<username>/dirA/.snapshots
# ls
. .. snap-20100808 snap-20100809 snap-20100810
# cd snap-20100809
# ls
fileA
# cp fileA /users/<username>/dirA/