Current status of Maths computing facilities...

September 13th update: problems with compute cluster submission node resolved

Problems with the Maths compute cluster submission node macomp001 are believed to have been resolved remotely but this system is being closely monitored to confirm this. These issues originally arose after ICT data centre staff had to cut power to the data centre in an emergency following a power blip on July 31st which stopped the cooling systems. When power was restored, macomp001 came back up before the college network which resulted in a low speed Ethernet connection being negotiated. This has since been fixed.

September 4th update: obscure issues with IPv6 connections

Some systems in Maths have been behaving strangely over the past 2 weeks or so owing to loss of IPv6 network connectivity. The symptoms encountered on affected systems include:

  • inability to connect to (which promotes its IPv6 IP address in preference to the IPv4 address)

  • long delays when using sudo apt-get update, sudo apt-get upgrade and sudo apt-get install commands on a Ubuntu Linux system

  • X forwarding over ssh no longer working when using graphical X Windows software such as Matlab, Maple, Firefox, etc remotely

The affected systems turn out to have IPv6 addresses but attempts to 'ping' remote systems on their IPv6 addresses using the IPv6 ping6 utility fail. The reason(s) for this are not yet fully understood but might be connected to the Huxley network switch replacement project that took place over the weekend of August 18/19th. A small number of systems with 100 Mbit/s network interfaces failed to reconnect to the college network afterwards, requiring manual intervention.

Restarting network services on some of these systems has resolved the problem but on many systems, this cannot be done because the IPv4 network is working and they are relying on this for their normal operation. There are temporary workarounds to these problem involving disabling IPv6 or telling apt-get to use IPv4 and not IPv6, for example. If you think your computer is not working as expected, please get in touch wth Andy Thomas for advice.

August 13th update: SCAN temporarily unavailable

The SCAN is temporarily out of service since there is a problem with updating the PXE configuration for the Beowulf HDB class to point tftp boot requests to ithe SCAN servers after they were moved from the old ICT data centre to the Maths server room in July. We are awaiting an update from ICT.

Andy Thomas

Research Computing Manager,
Department of Mathematics

last updated: 13.9.2018