On Wed, 2 Jan 2008, Derek Holzer wrote:
The whole idea of read-only is for two reasons:
- To protect the HD in case of unexpected shutdowns (which could happen
nightly in a typical museum situation)
The whole idea of a separate volume for /var that you see on Linux, and the whole idea of /var in the first place, is to allow the rest of the OS to be mounted read-only. (networked volumes were an afterthought added in the 80's, though it fits really well with the /var concept).
The logs normally go in /var. It's much quicker to do an integrity check on the /var volume than on the whole OS, plus it ensures that the OS won't panic like some Linuxes do when the / volume was improperly unmounted. On OSes that don't have that latter problem, it's still a good idea because then you're sure that a fuckup in /var won't affect any of the files on the / volume.
If you don't have a separate /var, you can still do the same using e.g. a USB flash volume or old USB hard disk, for all your logs. In general it's a good idea to keep logs of what's going on in your installation, to improve diagnostic when a problem occurs.
E.g. I used logs to detect a very slow memory leak, that would take two weeks to notice. By looking at the rate at which it occurred, I was able to guess the data type of the leaked memory! (this was before Valgrind made it easier to debug those). Even if you don't program, it's cool to be able to give those details in a bug report.
Also the logs can measure the time between crashes and report it, or even the consistency of framerate, etc.
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