CRAY XE6 Disk Storage
Users' HOME directories are located on a shared RAID system and are mounted via NFS on all login (frontend) and compute nodes. The path to the HOME directories is consistent across all nodes. The filesystem space on HOME is limited by a quota!
For large files and fast I/O Lustre based scratch directories are available which make use of the high speed network infrastructure (Gemini). Scratch directories are available on all compute and login (frontend) nodes via the workspace mechanism.
The available storage capacity of about 2.5PB has been cut into five areas:
|Univ_2||only few files per user (~1000)||no|
|Res_1||reserved for demanding projects||yes|
|Res_2||reserved for demanding projects||yes|
|Ind_2||shared acces with Viz cluster @ hlrs||yes|
The reason to split the Univ_1/2 filesystems is the time needed to recover from a failure. In case of a failure which requires a filesystem check , the time needed for this task is related to the number of files stored on the filesystem. To minimize the downtime after such a failure we separate users with a few (and probably large files only) to start production of the Cray system soon, while the group using the filesystem with about 100Mio Files will have to wait a couple of days (weeks) to become online again. Users / Groups may have access to Univ_1 or Univ_2 but not both.
IMPORTANT! NO BACKUP!! There is NO backup done of any user data located on HWW Cluster systems. The only protection of your data is the redundant disk subsystem. This RAID system is able to handle a failure of one component. There is NO way to recover inadvertently removed data. Users have to backup critical data on their local site!
Long term storage
For data which should be available longer than the workspace time limit allowed and for very important data storage, please use the High Performance Storage System HPSS