> Gesendet: Montag, 17. Juni 2013 um 21:29 Uhr
> Von: "David Anderson" <[email protected]>
> An: [email protected]
> Betreff: Re: [boinc_dev] Can we do shared memory with no disk usage?
>
> In situations were BOINC is causing unexpectedly large
> (> 1 GB/hour) disk I/O,
> we need to figure out the source of the I/O.
> -- David
My little centrino laptop had SETI (official client) run over night.
$ iostat -h -m
Linux 3.8-1-rt-amd64 (Toshiba) 06/18/2013 _x86_64_ (2 CPU)
...
Device: tps MB_read/s MB_wrtn/s MB_read MB_wrtn
sda
33.80 0.17 0.39 3040 6859
$ date
Tue Jun 18 00:30:06 CEST 2013
$ iostat -h -m
...
Device: tps MB_read/s MB_wrtn/s MB_read MB_wrtn
sda
65.32 0.07 0.98 3387 45737
$ date
Tue Jun 18 08:36:50 CEST 2013
Looking only at the last column, in those 8 hours this were
> (45737-6859)/1024
[1] 37.9668
GB and consequently
> (45737-6859)/1024/8
[1] 4.74585
GB/h
another machine, running about 10 clients in parallel (all Rosetta, one WCG),
had a bit less of IO ... here iostat was run twice with 1h interim sleep
twin1a:~ $ date ; iostat -m -h
Mon Jun 17 23:34:12 CEST 2013
Linux 3.2.0-3-amd64 (twin1a) 06/17/2013 _x86_64_ (24 CPU)
Device: tps MB_read/s MB_wrtn/s MB_read MB_wrtn
sda
3.08 0.02 0.30 29091 504228
$ sleep 3600 ; date ; iostat -m -h
Tue Jun 18 00:34:26 CEST 2013
..
Device: tps MB_read/s MB_wrtn/s MB_read MB_wrtn
sda
3.09 0.02 0.30 29091 506276
So this is about 2 GB per hour written and nothing read ????
And yet another machine, same hardware, mostly einstein with 1 Rosetta and 1 WCG
twin1b:~ $ date; iostat -h -m ; sleep 3600 ; date ; iostat -h -m
Mon Jun 17 23:58:16 CEST 2013
...
Device: tps MB_read/s MB_wrtn/s MB_read MB_wrtn
sda
1.67 0.00 0.12 75848 2377118
Tue Jun 18 00:58:16 CEST 2013
Device: tps MB_read/s MB_wrtn/s MB_read MB_wrtn
sda
1.67 0.00 0.12 75848 2379914
Which means another 2 GB per hour.
The machines were not running anything else but BOINC, the laptop had firefox
open in the background.
No BOINC graphical clients run anywhere.
iostat comes with the sysstat package, for anyone out there to try.
The laptop only has 1G of mem, which may lead to some swapping and account for
some of the IO. Still,
to me it looks mostly like some process writing a lot of status information
that is not read by anyone.
The missing reads for the big machines I might want to explain by large IO
buffers ... there certainly
have been a couple of uploads that should have caused some read, otherwise.
Cheers,
Steffen
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