20 Oca 2007 Cts 19:45 tarihinde şunları yazmıştınız:
[...]
> > vaio cartman # hdparm -tT /dev/hda
> >
> > /dev/hda:
> > Timing cached reads: 1576 MB in 2.00 seconds = 788.18 MB/sec
> > Timing buffered disk reads: 74 MB in 3.01 seconds = 24.55 MB/sec
> >
> >
> > [~]> time dd if=/dev/zero of=/tmp/1GB bs=1M count=1024
> > 1024+0 records in
> > 1024+0 records out
> > 1073741824 bytes (1,1 GB) copied, 77,2809 s, 13,9 MB/s
> >
> > real 1m17.482s
> > user 0m0.003s
> > sys 0m2.350s
>
> That's not bad at all ! I suspect that if your system becomes unresponsive,
> it's because real writes start when the cache is full. And if you fill
> 512 MB of RAM with data that you then need to flush on disk at 14 MB/s, it
> can take about 40 seconds during which it might be difficult to do
> anything.
>
> Try lowering the cache flush starting point to about 10 MB if you want
> (2% of 512 MB) :
>
> # echo 2 >/proc/sys/vm/dirty_ratio
> # echo 2 >/proc/sys/vm/dirty_background_ratio
After that I get,
[~]> time dd if=/dev/zero of=/tmp/1GB bs=1M count=1024
1024+0 records in
1024+0 records out
1073741824 bytes (1,1 GB) copied, 41,7005 s, 25,7 MB/s
real 0m41.926s
user 0m0.007s
sys 0m2.500s
not bad! thanks :)
Regards,
ismail
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