Re: hardware freezez and no clue where to start searching
On Thu, May 10, 2007 at 09:06:14AM -0700, AndiSHFR wrote:
> Here is an example:
>
> sv-vmhost02:/home# date ; time dd if=/dev/zero of=test.dat bs=1MB
> count=1000 ; date
>
> Thu May 10 17:53:45 CEST 2007
> 1000+0 records in
> 1000+0 records out
> 1000000000 bytes (1.0 GB) copied, 2.89129 seconds, 346 MB/s
>
> real 0m58.632s
> user 0m0.000s
> sys 0m3.480s
> Thu May 10 17:54:44 CEST 2007
>
> sv-vmhost02:/home#
>
> The date output shows that the dd did run from 17:53:45 to 17:54:44.
>
> But the dd command thinks it only took 2.8 seconds to create the 1 GB
> file -of course with a top thruput of 346 MB/s.
>
> But the time-command shows that the dd really took 58 seconds.
>
> So the real thruput was around 17 MB/s
>
> So i think the whole hardware is freezing an the os does not see it
> because there are
> no error messages in dmesg.
>
> When doing a "iostat -mxtc 1" during the dd it is shown that write
> thruput of the /dev/sda drops to zero for seconds (typically 10
> seconds) and then rises again.
>
> Any idea where to start searching for?
output of "hdparm -l /dev/sda" ?
--
Chris.
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