Re: tuning for mixed rate 800 stream write application

Stan Hoeppner [off-list ref] schrieb:

Hello fellow bcache users/developers,

A couple of questions.

1.  How do I disable write caching?
2.  How do I increase the sequential IO tracking window from 128 IOs to
say 4096 IOs or nmore?

I don't know which of the various knobs bcache considers but you can tune 
the IO window for the kernel IO scheduler with something like this:

#!/bin/sh

for nr_requests in 
/sys/bus/scsi/devices/[012]:0:0:0/block/*/queue/nr_requests; do
        echo -n 4096 >$nr_requests
done

I suggest switching to deadline also if you haven't done so yet.

Please note that my script tunes my SATA devices. I don't use bcache yet. 
You may want to adjust the line to work for the bcache devices.

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