IT Services



Backing up over wireless


Contents



1. Wireless Access to the HFS

The HFS service supports backup over the Oxford eduroam and OWL (with VPN) wireless for desktop/laptop machines. However, please be clear that wireless networks are not suitable for running full backups or backups of large amounts of data. This is because currently they have considerably less bandwidth than a normal, wired network connection, and the connection is sometimes subject to considerable interference. The practical application for backup over wireless is therefore for backup (or restore) of single, selected, small files and folders. Instructions on how to backup only selected items can be found here - Windows, Mac, Linux, Solaris, or command line.

For details on configuring eduroam access please see the IT Services eduroam pages.



2. Backup/Restore Speed

The key issue when accessing the HFS via wireless is that the performance of wireless is significantly lower than the performance of a wired connection to the University network. For this reason we recommend that the initial full backup to the HFS is carried out over a wired connection and ONLY small incremental backups or backups of a few selected files are carried out over wireless.

Usually, the connection is at least five times slower than a wired University network connection, and backup or restore will therefore take longer to complete. At worst, if the wireless connection suffers a large amount of interference, if you are a large distance from the wireless access point, or if there are many users connected to the same access point, then the speed of the backup could be lower. Approximate times for a wireless backup are given below:

Amount of Data
10MB 1GB 10GB
Good Connection
(30Mbps+ with good signal)
10mins 30mins 3hrs
Medium Connection
(20Mbps with medium signal)
15mins 50mins 6hrs
Poor Connection
(10Mbps or lower / poor signal)
35mins 3hrs 20mins 29hrs
Wired University Network
Connection (100Mbps)
10mins 15mins 35mins

These figures include an approximation for starting the session with the HFS and scanning the disk for files to back up - this takes around 10 minutes on an average machine.

The time taken to restore data from the HFS is roughly the same as the time taken to backup the same amoutn of data, please see the table above.



3. Problems

There are a number of problems associated with using wireless which can cause backups to fail or stop. If you experience problems with your connection to the HFS please try using a wired connection first to see if the problem persists. Then see our help and support pages and if necessary contact your local IT support staff. If they are unable to resolve your problem, please email hfs@ox.ac.uk.



4. Points to Remember

Please take note of the following: