Links August 2008Links August 2008
Michael Janke is writing a series of posts about estimating availability of systems, here is a link to the introduction [1]. He covers lots of things that people often miss[...]
Month: August 2008
Improving Blog Latency to Benefit ReadersImproving Blog Latency to Benefit Readers
I just read an interesting post about latency and how it affects web sites [1]. The post has some good ideas but unfortunately mixed information on some esoteric technologies such[...]
Swapping to a Floppy DiskSwapping to a Floppy Disk
In the mid 90’s I was part-owner of a small ISP. We had given out Trumpet Winsock [1] to a large number of customers and couldn’t convert them to anything[...]
Killing Servers with Virtualisation and SwapKilling Servers with Virtualisation and Swap
The Problem: A problem with virtual machines is the fact that one rogue DomU can destroy the performance of all the others by inappropriate resource use. CPU scheduling is designed[...]
Is SE Linux Unixish?Is SE Linux Unixish?
In a comment on my AppArmor is dead post [1] someone complained that SE Linux is not “Unixish“. The security model in Unix is almost exclusively Discretionary Access Control (DAC)[...]
Xen and Linux Memory Assignment BugsXen and Linux Memory Assignment Bugs
The Linux kernel has a number of code sections which look at the apparent size of the machine and determine what would be the best size for buffers. For physical[...]
Play Machine DowntimePlay Machine Downtime
From the 13th to the 14th of August my Play Machine [1] was offline. There was a power failure for a few seconds and the machine didn’t boot correctly. As[...]
AppArmor is DeadAppArmor is Dead
For some time there have been two mainstream Mandatory Access Control (MAC) [1] systems for Linux. SE Linux [2] and AppArmor [3]. In late 2007 Novell laid off almost all[...]
Switches and CablesSwitches and Cables
I’ve just read an amusing series of blog posts about bad wiring [1]. I’ve seen my share of wiring horror in the past. There are some easy ways of minimising[...]
Purging an RT DatabasePurging an RT Database
I had a problem where the email address circsales@washpost.com spammed a Request Tracker (RT) [1] installation (one of the rules for running a vaction program is that you never respond[...]