Lost File Recovery
Home Directories is protected against accidental file deletion through a series of snapshots taken every night just after midnight. Each snapshot provides the state of your files at the time the snapshot was taken. It does so by storing only the files which have changed between snapshots. A file that has not changed between snapshots is only stored once but will appear in every snapshot. This is an efficient method of providing snapshots because the snapshot system does not have to store multiple copies of every file.
These snapshots are kept for a limited time at various intervals. ITaP keeps nightly snapshots for 7 days, weekly snapshots for 4 weeks, and monthly snapshots for 3 months. This means you will find snapshots from the last 7 nights, the last 4 Sundays, and the last 3 first of the months. Files are available going back between two and three months, depending on how long ago the last first of the month was. Snapshots beyond this are not kept.
Only files which have been saved during an overnight snapshot are recoverable. If you lose a file the same day you created it, the file is not recoverable because the snapshot system has not had a chance to save the file.
Snapshots are not a substitute for regular backups. It is the responsibility of the researchers to back up any important data to the Fortress Archive. Home Directories does protect against hardware failures or physical disasters through other means however these other means are also not substitutes for backups.
Home Directories offers several ways for researchers to access snapshots of their files.