Backup Services

Backup process fundamentals

• A full backup is performed once a month.
• All workstations are divided into four backup groups.
• Once a week (on a specific, regular Friday) a full backup is performed of one backup group, thus every station will receive a full backup once per month. For example, the station acc.tau.ac.il belongs to backup group 1. This group is backed up on the first Friday of the month.
• Incremental daily backup is performed every day (Sunday to Thursday) throughout the month. A backup is performed only for new files or files changed since the last backup.
• The backup is saved for a period of two to three months.

Thus, on any given day the size of system storage for a station is the sum of all tape spaces on which two to three full backups are stored, and all the daily changes that have taken place between them.

Example :

• A station with a disk space of 100GB and an average daily backup of 100MB (0.1GB) is added to the backup services.
• For three months, there are three full backups, e.g. 300GB and another 66 days with incremental backups (0.1GB*66) for a sum of 6.6GB.
• The average daily size after three months of backup for this data is about 306.6GB.

For your consideration :

• The backup system saves all the backups made over the last three months on the tapes. Thus, every day for three months after joining the service, a backup with an average size of the final backup of the third month is saved on the backup tapes.
• The backup system sends daily e-mails to the station owner and/or support personnel regarding the integrity of the backup made that day, the number of files backed up, and their size (please note that the notification will not include the total size of all backups present on the backup system that day).