Server Backups
Data on the server Astro is backed up nightly and backup set span one week. To retrieve files from the backup please contact the Astrophysics Help Desk. There is NO BACKUP SYSTEM FOR THE SERVER WINK however the raid array provides one level of redundancy. If a disk fails your data will be intact, if a second disk fails all data will be lost. Ensure you backup all your files regularly.


Backing up your desktop or laptop to another machine using rsync
An easy way to backup the linux partition on your desktop machine or laptop is by using the rsync command. rsync provides potentially fast local or remote incremental data transfers. It is fast because rsync can synchronise data by copying only the differences between source and target data. rsync can use Secure Shell (SSH) to improve security by encrypting the session. On newer FreeBSD workstations rsync defaults to SSH where as other operating systems such as Linux may not (in which case it is necessary to add the -e ssh switch).

Rsync must be installed on both the source and destination computers. All of the main Physics workstations include rsync. If you need to install the program on your local workstation you will find most major Linux distributions such as Debian and Fedora have packages available. Else, visit the Rsync home page to download the source:

Below is an example of how to backup the contents of  /home/user/thesis on your workstation to the directory /home/user/data/backup

rsync -an --delete -e ssh /home/user/thesis/ user@astro:/home/melinda/data/backup/ 

Note that the trailing slashes do matter. The above command will copy all the files and directories from /home/user/thesis to /home/melinda/data/backup/

If you issue the command:

rsync -an --delete -e ssh /home/user/thesis user@astro:/home/melinda/data/backup/ 

The subdirectory "thesis" will be created in /home/melinda/data/backup/. For more info on backuping up with rsync visit Mike Rubel's page.

IMPORTANT! The -delete command is extremely dangerous and should be used with care, since it makes the source and destination identical, even if it means deleting data in the destination directory. Use the -n switch (``dry run'') to simulate the rsync transfer beforehand.


Backing up to DVD+/-RW
There are 3 DVD writers available for use in the department:

  • There is a DVD writer on astro. This provides an easy way for you to backup your data to a portable medium once you have finished with it. The capacity of the DVD+RW disk is 4.7GB and the DVD+RW disc can be read in mosts DVD-ROM drives (ie readers). Note that the DVD+RW discs are rewitable and we cannot write to DVD+/-R disks on astro due to a firmware limitation in this first generation DVD burner. To backup using the DVD burner on astro your must contact the Astrophysics Help Desk.
  • A dual layer DVD+/-RW burner (8.7GB) is located in the general access PC. Data must be sftp'd over to the PC for burning.
  • A portable DVD burner available from Rm 132. This connects via firewire or USB2 (USB 1.0 does not provide the throughput neccessary to burn a DVD) to your PC or laptop.

DVD disks are currently not available at the store, you are required to purchase your own.