The data on all the cluster volumes (/home1, /home2, /home3, etc.) are mirrored to other hard-disk volumes.

• /home1 is mirrored to space in the NCSU HPC Center.
• /home2, /home3, /home4, /peng_1, /pengseq, and /gt4sp_1 are mirrored to misterscott in Ricks Hall.
• /home5 and /home6 are mirrored to geordilaforge in Ricks Hall.
• /aylor_1 is mirrored to zeframcochrane in Ricks Hall.
• /gt4sp_2 is mirrored to leahbrahms in Ricks Hall.
• /bochica is mirrored to bochicabak in Ricks Hall.

The mirroring is done once per week on each volume.

We have limited space for keeping old backups, but we now (as of June 2019) keep the last 4 mirror copies of the data. If you accidentally delete a file and wait more than a month to ask a system administrator to recover it, they won't have it. But in the case of a real disaster happening to the cluster itself, we will have a pretty recent copy of the data.

We have a tape drive (and some tapes) for archiving old data, and making extra copies of important data. If you have any (large chunks, 0.5TB or more, of) data that you are no longer using we can copy this to tape and free up some space on the cluster.

The tapes are LTO-6 and hold 2.5TB of raw data each. The tape hardware attempts to compress the data as it writes it to tape. This can mean up to 6TB of data written to tape. For our data I have often seen 4TB written to one tape, but also very little compression in cases where the data are already compressed.

If you have students who have left the university and are no longer using their cluster account, their data could be archived to tape. In either case please let the system administrators know. (Old accounts may be archived to tape anyway - see the note on data retention below.)

In general accounts which appear not to have been used for more than 6 months will be locked and the data belonging to the account may be archived to tape. Access to archived data can then be obtained by contacting the system administrators. Recovering the data may take up to a few days (depending on whether the tape drive is busy with another job, how much data is to be recovered, holidays and weekends).

Data archived to tape will be kept for a minimum of 5 years. After that the tape may be re-used. If you would like your archived data to be kept for longer than that, please contact the system administrators to discuss it.

Please see the page on Sensitive Data for a discussion of this other form of data protection.