On Jul 19, 2011, at 3:15 PM, Dinse, Gregg (NIH/NIEHS) [E] wrote:
> I have a Mac Pro that is making an odd clicking sound, which I assume is
> coming from either a hard drive or a DVD drive. It seems to make noise for a
> few seconds and then is quiet for about 10 minutes. This pattern (on for 2
> seconds, off for 10 minutes) seems to repeat itself all day, but there is
> enough other noise in my office (and I often get distracted or I am out of
> the office at times), so I can't swear that it never takes a break.
This sort of noise is almost always a hard drive, and is also almost always a
precursor to drive failure. I've had several dries do this (one manufacturer
even told me it was 'normal' until I finally showed them logs showing the write
speed fluctuating widely).
Make sure your drive is baked up, and then try to run some tests to see if you
can cause an error on the drive, or cause a slow-down.
a good way to check your drive's speed and also highlight any problems is to
write a massive file of zeros to your drive using the unix tool 'dd'.
Something like this:
dd if=/dev/zero of=test_data.bin bs=1024k count=10240 2>&1 | \
grep "byte" | cut -f7 -d" "| sed 's/(//' | \
awk '{printf($1" bytes per second (%.2f MB/s)\n", $1/1024/1024)}'
will create a 10GB file of zeros ('if' is short for 'input file' and /dev/zero
simply spits out zeros) and will show you the maximum hard drive speed overall.
If you hear clicking , you can use rsync -aP to copy that file to another file
and see the real-time speed progress.
rsync -aP test_data.bin tes_data2.bin
The dd numbers are essentially meaningless. What you care about is if there is
a delta in the speed when you hear the clicks and when you don't. If you get
115MB/s on one test without clicks and 85MB/s on a second with clicks, you will
know the drive is the issue. I would be seriously concerned over any drop of
more that 5-10%.
If you have multiple drives, you will have to run this test on each drive, once
with clicks and once without to isolate the problem drive.
--
"If this was a dictatorship it would be a lot easier; as long as I was
the dictator." -- George W Bush
_______________________________________________
MacOSX-talk mailing list
[email protected]
http://www.omnigroup.com/mailman/listinfo/macosx-talk
