Philip Molter wrote:
Mike Hardy wrote: [ ... snip ... ]The readahead is the first place I'd look though. All in all, it appears that 2.6 kernels need a great deal more I/O tuning before they can be put in production. While I like the flexibility that's available, the default settings seem to be a major negative change from 2.4. This sort of thing is just now being quantified and hopefully it gets sorted out in the next couple of releases
[ .. snip ... ]
My first suspicion was readahead as well, but I couldn't find any of the sysctl options to control readahead in the kernel (as there were under
I'm honestly not trying to be a smart-ass by posting this since I haven't played with these *a single bit* - however, this was what I found:
<berlin>/sys % find . | grep ahead ./block/hdf/queue/read_ahead_kb ./block/hdg/queue/read_ahead_kb ./block/hdc/queue/read_ahead_kb ./block/hda/queue/read_ahead_kb
Maybe those are the appropriate knobs to twiddle? If so, it appears they've gone per-device, and they've moved to sysfs...
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