Server hosted

What data is backed up

Regarding backup there is a separation of server based and PC based data:

• Server hosted data is always online and thus can be reached by the nightly backup job from the central backup system
• PC based data is in principle offline, even though the PC regularly is connected to the DTU Compute network, and hence this data cannot 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 with 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 copies of the data are then always online and become part of the daily backup routine.

All server based data is included in the daily backup routine. Applications, distributions or other data that are online on the Internet or exist on other media such as DVDs etc. are not included in the data sets that are being backed up.

How often are backups made

The backup frequency depends on the type of data. This is due to the simple fact that we are capable of making a backup of all data within one night. Data is split into five categories: User data, project data (with backup), project data (without backup), distribution data and scratch:

• User data - Users home directories, copy data from locally stored data (desktops and laptops), common folders (such as the common area on nas1, web files on www2). 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 backup of this data is done weekly (every weekend).
• Nobackup data and dtu-compute data - are being copied daily to a secondary server and retain snapshots for one week. No further backup.
• Distribution data - Data which for the sake of convenience are put online, but where the source is an ISO or similar media. Distribution data is not backed up.
• Scratch - Temporary and easily reproducible 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:

• A Full backup is stored for 84 days. A monthly backup is kept for one year.
• 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 archiving first goes to disk storage and then after a period it is transferred to tapes for storage.

How long archives are stored

Archived data is stored for as long as the tapes can be read. The current tapes (HP LTO-7 Ultrium) are warranted a 30 year lifetime from the manufacturer. 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 with the assistance of external companies (the use of external companies implies a costly restore process in terms of time and money).