Keep tweaking the kernal parameters a bit to see if it helps, but it seems you can't give it a true 'do this when memory runs low'
OOF needs a fairly modest 100Mb RAM approx, sometimes less, sometimes a bit more. Linux, like most OSes, does the decent thing and uses the remaining RAM for buffers and disk caching. Great
Until it runs low on memory available memory (not used by app or by caching). Here, every other OS in the world releases a bit of caching memory to make RAM available. Sensible choice. Linux, by default, starts SWAPPING (ie, using the disk as extention to RAM), which obviously causes disk utilisation to go up, and app to slow down. Then, more web requests come in, and as old requests not yet dealt with (as system is paging heavily), more memory is needed, but not available, so yet more swapping, and the thing grinds itself towards a crash, as ultimately it runs out of swap as well. Whatever idiot came up with that strategy - yes, thats you Linus - should be strung up.
It doesn't matter how much memory is present, with this strategy, the server will consume it all, then consume all swap, then crash. Extra memory just delays the inevitable.
At least in the later kernels, there are a couple of tweaks.
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Topic: what happened (Read 1090 times)