Storage Policy for Falcon and Colt

Hardware and software support for the CCS and ORNL production mass storage systems is provided by the Storage Systems group of Computer Science and Mathematics Division's High Performance Computing Section.

Types of storage

We have four types of storage available to Falcon and Colt users: DFS, CFS, PFS, and HPSS.

• DFS (Distributed File System) includes each user's home directory. This is online disk intended for permanent, frequently used storage and is backed up on a daily basis.
• CFS (Cluster File System) is a cluster-local file system that has a limited amount of space for user files. Users may request CFS space by contacting the consultants. User space in CFS is not backed up, and no space restrictions exist beyond the hardware limitations of the user-space CFS partition. Users should move CFS files that are not being actively used to DFS or HPSS.

• PFS (Parallel File System) is a large fast disk area intended for shared access to temporary storage, for example, to hold output generated by your job. It is not currently backed up. Users should move PFS files that are not being actively used to HPSS.
• HPSS (High-Performance Storage System) is the archival storage system. It consists of a terabyte (TB) of disk cache and hundreds of TB of robotic tape storage. HPSS may be accessed using HSI ("hsi").

Projects should not duplicate executables or datasets in each user's area but should set privileges to share a master copy. Contact the CCS consultants for help in setting up a DCE group to facilitate sharing. Files not in immediate use, such as source code and output datasets, should be moved to HPSS.

Space allocations

• A research account is entitled to 500 MB (0.5 GB) in DFS. With sufficient justification, it is possible to have 1 GB. For projects with special requirements, we will consider extensions of this limit on a case-by-case basis.

• Files in CFS and PFS should not be retained for more than one week and should be migrated to HPSS as soon as the files are not being actively used. Because of the working-directory character of CFS and PFS, we have not yet set a space limit for usage. If we find that users are frequently leaving files in CFS and PFS for more than one week, we may have to restrict usage to ensure that we have enough disk space available to run large jobs.

• Space in HPSS is for files that are not needed immediately. We have not yet set a space limit for HPSS usage. Even though HPSS is a very large storage system, space is not unlimited. Users must not store files unrelated to their CCS projects in HPSS. They must also review their files periodically and remove unneeded files.

Consequences of abuse

Storage usage will be monitored periodically. If time permits, first offenders will be warned to clean up their space. Ignoring these warnings will result in loss of access privileges.

If a file system runs out of or gets low on space, user data in that file system will be subject to involuntary deletion without prior notice under the following guidelines.

• CFS and PFS files that have not been accessed in the current week (seven-day rolling window) may be deleted.

• Files to be deleted will be selected randomly; there will be no attempt to guess which files are more valuable to the user.