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Backup Policy

SEASnet Backup and Tape Storage Retention Policies

The following policies are in effect regarding data on SEASnet servers and on user machines that have backup support from SEASnet.  These policies apply to both electronic mail and filesystem data for faculty and staff.  These policies are designed to ensure that accidentally deleted data may be retrieved, if necessary, for a reasonable period of time and provide individuals with a clear timetable concerning retention of their data. SEASnet recognizes that it is important for users to know that their data is restorable in the event of accidental or catastrophic data loss, but also that data is not being retained beyond a useful period of time.

Background Information

SEASnet provides snapshots of data and email maintained on our servers. “Snapshots” are taken at various intervals during each 24-hour period (see schedule below). Snapshots taken of users’ data files allow users to restore data accidentally deleted from their account without intervention from SEASnet (Note: this is only possible with data files – SEASnet staff must intervene for all email restorals).  SEASnet maintains snapshots for approximately one to two weeks.  Step-by-step instructions for restoring deleted files can be found here.

Backup Schedule


Home directories, Maildir and other filesystems

Backup Level Frequency Storage Retention
Full backup monthly Tape 3 months
Differential weekly Tape 3 months
Incremental* daily (Mon-Fri) Disk 4 weeks

*does not include PC backups

These policies are not a guarantee that data will not be retained, either intentionally or accidentally, beyond the time periods listed above.

Snapshot Schedule

File systems residing on netapp filers
(both Maildir and Other Filesystems)

Snapshot Type Snapshot Time Storage Retention
hourly snapshot every two hours (9am-11pm) Disk (.snapshot) 1 day
daily snapshot midnight (Mon-Sat) Disk (.snapshot) 8 days
weekly snapshot midnight (Sun) Disk (.snapshot) 2 weeks

These policies are not a guarantee that data will not be retained, either intentionally or accidentally, beyond the time periods listed above.

Definitions

differential backs up files, within a filesystem, that have changed
since the last full backup of a filesystem – if utilized in
conjunction with a full filesystem backup, it enables the
complete restoration of a filesystem at the time of the current backup
full a backup of all data within a given filesystem – it
enables the complete restoration of a filesystem at the
time of the current backup
snapshots snapshots are a feature of the file server used by
SEASnet to store user and electronic mail data;
they create virtual images of a filesystem and all data
at the time the snapshot is created – this enables
convenient retrieval of lost data up to the retention time
of snapshots