Backup
Contents
What data is backed up?
Regarding backup there is a separation of server based and pc based data:
- Server based data is always on line and thus can be reached by the nightly backup job from the central back up system
- PC based data is in principle off line, even though the pc regularly is connected to the DTU Compute network, and hence this data can not be included in the central backup routines.
It is recommended that all data as far as possible is stored on central servers so that it is assured to be included in the daily backup routines. Laptop users who need to maintain a local copy of data to bring them when leaving the DTU Compute network can of course store their data locally on the laptop. They are then required to conform to specific procedures for synchronizing specifically chosen data (folders) to a central server. These server based copy-data is then always on line and becomes part of the daily back up routine.
All server based data is included in the daily backup routine. Applications, distributions or other data that are on line on the Internet or exists on other media such as DVDs etc. are not included in the data sets that being backed up.
How often are backups made?
The backup frequency depends on the type of data. This is due the simple fact that we are capable of making of back up of all data within one night. Data is split into four categories: User data, project data, distribution data and scratch:
- User data - Users home directories, copy data from locally stored data (desk- and laptops), common archives/folders (such as the common area adserv1 and e-mail. A full backup of this data is done weekly (every weekend) as well as a daily incremental backup
- Project data - Data belonging to a specific project (primarily research projects). A full back up of this data is done weekly (every weekend)
- Distribution data - Data which for the sake of "easiness" are put online, but where the source is a DVD or similar media. Distribution data is not backed up.
- Scratch - Temporary and easily reproduce able data. Scratch data is not backed up.
How long backups are stored
Backups are stored for different periods of time depending on the type of backup:
- Full backup is stored 84 for days
- Incremental backup is stored for 6 days
Archiving of Data
When a user account or project expires all relevant data, meaning user and project data, is archived. The archieving first goes to disk storage and then after a period it is transferred to tapes for storage.
How long archieves are stored
Archived data is stored for as long as the tapes can be read. The current tapes (HP LTO-4 Ultrium) is from manufacturer warranted a 30 year lifetime. Due to our usage, storage facilities and changes in technologies we estimate that archived data can be restored "locally" for at least 1 year and at least 5 years by the assstance of external companies (the use of external companies implies a costly restore proces in terms of time and and money).
Backup on Windows
Backup on Linux / OSX
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