Normal service ought now to have been resumed.

In my case, the big pause in posts has gone on for two months now. In fact, I’ve been busy with another project, which ironically is a time management tool. I don’t intend to let this blog lapse entirely, but right at the moment I’d rather do one side-project well than two badly.

If you’re interested, please head on over to TaskMaster and let me know what you think, either here or at the feedback forum. It’s at an early stage, and is at least a week or two away from being ready for ordinary users (there’s very little documentation at the moment, so it’s probably not obvious how to use it). I’ll update here and on the TaskMaster blog when there’s some significant progress.

As of a month from now, I’ll be moving to Zambia where I will be living and working for at least three months. I’ll be working in a technical role for a local ISP. On the surface my job description may not be all that different, but I expect the culture and business environment to be a radical departure from the UK.

The main difference to this blog is that I intend to post more about the experiences of preparing for and living abroad, in the hope that some of this will be of interest to others. People who were expecting a blog on technical topics (something I never stuck to particularly well) may be inconvenienced by this. I had thought about starting a separate blog, but for such a short-term period it hardly seems worth it.

According to top the percentage of time the CPU is in the wait state is close to 25%, which on 4 (virtual) CPU’s means I’m probably blocking entirely on I/O. Since I’m shifting around a few kilobytes of data, disk access ought to be trivial. The only likely candidate is swap usage, and sure enough I’m running with only a few meg of physical memory free.

I’m hosted on a minimally-sized Slicehost slice, which means I have 256Mb of physical RAM to play with. Apache is using 220Mb of virtual address space, and MySQL is using 158Mb, so both ought to be candidates for optimisation.

This post talks about optimising MySQL for a small slice, but doesn’t reach any firm conclusions. I can obviously cut down my MySQL caches quite a bit compared to the stock config file, so I changed the following:

key_buffer = 8M
query_cache_size = 8M

Both settings were reduced from 16Mb, which frees up 16Mb. Apparently the sort buffer is another variable that can be reduced since I shouldn’t have too many large data sets to sort.

sort_buffer_size = 128K

Changing this setting took effect (as evidenced by SHOW VARIABLES), but didn’t result in any reduction in memory use reported by top – perhaps this buffer is allocated and freed when a sort is in progress? Net effect is that MySQL is now using 142Mb.

On the Apache side, this post suggested disabling apache modules that aren’t in use. I disabled mod_cgi, which seemed to take Apache memory usage down to 200Mb. I also ought to be able to optimise the server for low traffic by tweaking the number of threads. I discovered I was running the prefork MPM by running:

$ /usr/sbin/apache2 -l

This meant I could use the settings the post suggested by reducing the minimum number of servers available. I turned both StartServers and MinSpareServers down to 1, and reduced MaxSpareServers to 5. After this Apache still has the same footprint per process, but there are fewer processes running so memory usage is reduced. It’s hard to estimate how much since the footprint per process reported in top contains an unknown amount of shared libraries that don’t add extra overhead per process.

The final score is that there is now around 100Mb physical memory free on the box, compared to 4-6Mb before I attempted to optimise. The blog feels much nippier, though that could be partially due to the effects of caching.

First, the practical reasons: I need somewhere to write stuff that I want to announce to nobody in particular, but is too big to fit in a tweet. In the past I guess these kind of things might have been posted to Usenet, but those days are gone. I used to use Drupal for this, but I finally came to the conclusion that this was just a blog by any other name.

Secondly, there has been a technological change (albeit one where I am late to the party): RSS, twitter, delicious and various other link-sharing media have more or less obviated the difficulty of ploughing through posts that don’t interest you or blogs that haven’t been updated. It seems that whatever pretence had existed of blogs being a coherent series of time-based updates has been replaced with an à la carte approach where people can pick and choose what they want to listen to.

So why did I have so much hate for blogs in the past? I think one of the reasons also forms the root cause of my change of heart. Back in the good old days, there was a certain amount of optimism that the internet would be used for stimulating dialogue and exchange of ideas. At the time I was a keen student of Neil Postman, and saw an answer to many of the mysteries of modern society in his idea that changing the medium of exchange alters the sorts of social interchange that can be had, and potentially alters the whole course of society. To me, blogging seemed an obvious case of a medium with insidious weaknesses: encouraging input from uninformed amateurs, and drawing focus to the frivolous daily events over longer-term issues.

In recent years the position of blogging seem to have swung the other way: social media increasingly allows us to take part with almost no effort barrier to entry (Twitter being the obvious example). In this world blogs stand head and shoulders above the landscape by being written in complete sentences and expressing coherent thoughts with appropriate context.

So maybe I was wrong about blogging in particular, though I believe I was largely right about the shift in communication style and content. It’s worth noting that some of the problems thrown up by technology (wasting time reading blogs) have been solved by further technology (RSS). I remain an optimist about the possibilities of technological progress, provided we don’t accept change uncritically.