05 June 2008

Visual/spatial logic on Squid & on children

The Problem

I ran across an example of visual/spatial perception today which fell into place when I thought about how I’d arrived at a conclusion which happened to use it.

Customer was using Squid at a remote office to interact with intranet work pages served by Apache from a central machine.

Clients were sometimes getting good results, sometimes getting part-pages, occasionally getting nothing.

This did not “feel” right for either Squid or Apache, either of which tends to die fairly obviously, with an error page or a log entry, or both.

So I asked a simple question: did the internet pages get fetched over the VPN (OpenVPN) or directly? Through the VPN. Hmmm.

Careful scanning of the VPN config files revealed that it was using ping & ping-restart to keep the link alive. The ping time had been set to 280 seconds, which is right for not hammering the NAT/Masquerading on a router, which is often set to timeout at 5 minutes (300 seconds). The ping-restart time, however, was much less, at 120 seconds.

This meant that the link would be shut down & rebuilt about every 6 minutes, which syslog showed was happening. Setting them to 230 & 280 then restarting the openvpn service resulted in steady operation.

The lesson?

Thinking about the process visually/spatially (wholistically), rather than in terms of the operations of individual components, had yielded an effectively instantaneous solution. Customer had spent days approaching it from an auditory/sequential perspective & is definitely not a dumb bunny.

The children

I know a young lad & his sister who think like that, with an even younger brother who hasn’t yet had to show his stripes — but odds are strong that he will think alike too. In fact, I’m willing to bet that the youngest also has an emotive cognate like his sister & a niece of mine (niece can walk through a room in seconds & then tell you how the people in it are feeling, how they’re related to each other, etc).

I really do hope to get an opportunity to work with these young geniuses to find out how to actually use this talent rather than ignoring it, letting it be buried under the mundanity of a school which clearly does not understand how these yungun’s actually work.

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