Standard Backup Retention Policies
These are the standard backup policies for users that have contracted with UF-IT's Tivoli backup group to provide backups of their data on Research Computing systems.
How Policies are Applied
The concepts of Tivoli backup are that a "Node" has a policy applied to it. The node can have multiple file spaces backed up to it, but only one policy can be applied to the node. The file space utilization of a node is what the customer is charged for by ICT/NSAM.
If you have the need for more than one policy to be applied to different file spaces, multiple nodes will need to be created in order to facilitate the different policies.
Default Policy Settings
|Versions Data Exists||7 copies||This policy applies to both live and deleted files excluding the last copy of a deleted file. If a file is changed, the old version of the file is held in backups up to the time limit set in Retain Extra Versions. If more versions of this file are backed up, the oldest version of the file will be dropped from backups.|
|Versions Data Deleted||5 copies||If a file is deleted, this setting takes effect on the retained copies of the file. If there were more versions of the file on the system as defined by Versions Data Exists, then oldest extra versions will be dropped from backups.|
|Retain Extra Versions||60 days||The number of days that extra versions of a file will be held in the system.|
|Retain Only Version||90 days||The number of data that the last version of a file that has been deleted will be held in the system.|
How Files are Stored
When a file is stored on the Tivoli system, it is written to tape (and then is mirrored to an offsite location). In addition to this, where it is stored on tape along with other metadata about the file is stored in a catalog.
When a file is changed, the new version of the file is also written to tape, an entry is made in the catalog, and the catalog entry for the old version of the file is marked with an expiration date as defined in the policy settings for backup.
When a file is deleted,
So now, what happens when the date is reached where the old version of the file expires?
- The tape inventory is updated with the file being marked as removed.
- The entry in the catalog is removed
Requesting a file recovery
If a file needs to be recovered from the Tivoli system, please submit a service request in Research Computing's ticketing system at http://support.rc.ufl.edu
Costs for Backup
The cost for backup to the Tivoli backup system is $78/TB/Year, or $6.50/TB/Month. This is the cost of the data stored on tape, and there are no transfer fees for backing up to tape or recovering data from tape. In addition, the quotas involved on the system are not involved with these backups. The backup space used is based on a combination of the contents of the directories that have been designated by the user, deleted files that are within the retention period, and changed files in the retention period.
As a general rule of thumb, you can expect to be charged approximately one and a half times the amount of space you are actually taking up on the filesystem due to changed and deleted files being retained for the periods listed above.
- On a regular basis with backups, we see backup errors of files that were not backed up due to changing while the backup process was running on them. This typically occurs for two different reasons:
- The file was deliberately modified, either by the user or a job running. If the file is a permanent file, it will be backed up the next time the backup process occurs in one day.
- The file is a temporary file being utilized by a job. These files are by nature temporary, so it is actually a good thing that the file is not backed up, as the next time the backup process runs it will not be there, and will not be backed up. Some temporary files are backed up from time to time, only to be marked as deleted the next time the backup runs. These files will remain in the backup system for 90 days, the length of time it takes for a file to expire after being deleted.