Current status of Maths computing facilities...

December 6th update: no reported issues

There are currently no reported problems with Maths systems and services although the SCAN is temporarily out of service owing to technical issues with migrating the service to operate with PC clusters that have been changed from legacy BIOS booting to UEFI booting.

Known network issues

Although not a 'mission critical' problem, it is now known that some links within the internal networks in Huxley 616 are not operating at the highest speeds they should be and a few of the network connections to some systems are operating at 100 Mbit/s instead of 1000 Mbit/s (gigabit) speeds. To users, this means file and data transfers to & from some systems can take as much as 10 times longer than they should do. Individually, the systems, inter-connecting cables and network switches are all functioning correctly but in some cases the end-to-end link speed is being negotiated at the slower 100 Mbit/s speed and not gigabit.

This is believed to be caused by physical cable congestion in the increasingly confined space underneath some of the racks, resulting in cross-talk between bunched network cables and possibly interference also from adjacent power cables and metalwork. The data signalling within a standard network cable is effectively a weak UHF radio frequency connection running through 4 twisted pairs of wires in an unshielded cable and is prone to interference. So a programme of relocating rack cabling will begin in January 2019.

Andy Thomas

Research Computing Manager,
Department of Mathematics

last updated: 6.12.2018