Configuring CUPS to print to papercut queues Out of the box most Linux systems (and Macs I believe) come configured to use their own local cups daemon. The simplest way to print to papercut is to configure a queue on this service. 1. Check that client.conf isn't … [Read more...]
Lessons from the LR4 upgrade
The upgraded AV system is now installed in LR4- news item to follow. We were faced with a number of challenges and I thought I'd talk about some lessons that came out of the exercise. One of them is that EDID (Extended Display Identification Data) management is not as … [Read more...]
shooting myself in the foot #2 (symlinks, thank goodness for backups)
Note to self: if you use rsync (or cp -ar, or ...) to make a copy of an existing directory, things that are symlinks to absolute paths in the original will also be symlinks pointing to the same original absolute location in the copy. Fortunately, we had good backups. … [Read more...]
shooting myself in the foot (#1 of many) (rebooting stuck web-servers)
A long time ago, a web server I look after (divf.eng.cam.ac.uk) would regularly get into a (irretrievably) wedged state, and a while later people would complain. It was unobvious what was causing this, and disruptive that it was happening. So as a quick fix, I wrote a … [Read more...]
using the university maps for conference handouts
We have a conference that wanted to hand out maps to its delegates. Having spent a bit of time working out how best to use the university map server for this purpose, I've created a quick "How To" to save other people time: Using the university map service to create … [Read more...]
Dells, power cuts, drastic loss of performance
Last weekend, the speech group noticed that one batch of their compute servers was running much slower than they expected (compared to other, older machines). Exactly one of the newest batch was running fast, but the remainder were going perhaps 50% slower than was … [Read more...]
zfs resilver tuning
The zfs resilver delay is the amount of time in seconds zfs waits after any zfs io before queing any resilver operations, to avoid degrading performance. The default on oursystem appears to have the resilver delay as 2. With that set, it takes 10+days to rebuild a disc … [Read more...]
Virt-manager and Centos 7.1 kvm hosts
After the upgrade from 7.0 to 7.1 I started playing with virtual kvm hosts again. The good news is that migration seems now not to have the bug where sometimes the domain would not freeze just after transfer. The bad news is that in virt-manager on 7.1 the default mode … [Read more...]
Converting from our Kwiki
The ITSD Wiki is an old perl application that's no longer supported as far as I can see. The pages are written in a non-standard markup, a disincentive to copying information to/from the Kwiki, and perhaps a disincentive to contributing to the Kwiki. I've looked around for … [Read more...]
Dyson Building and Design Centre
If I haven't posted anything on here in a while it's because I am currently working with the project teams for the new James Dyson Building and Dyson Design Centre in designing the audio visual systems for the spaces. CUED AV Support will be … [Read more...]