Re: System unresponsitive when copying HD/HD

From: Jens Axboe (
Date: Sun Feb 04 2001 - 20:07:16 EST

On Sun, Feb 04 2001, LA Walsh wrote:
> Seems to have gotten a bit worse. Vmstat output after 'vmware' had completed
> write -- but system unresponsive and writing out a 155M file...

Your numbers seem way too much off to have much to do with i/o scheduling
fairness, but there is a slight bug due to the merge and insertion scan
being done at once now. So you could try with attached patch and see
if it makes any difference whatsoever.

> Those columns are output from a 'vmstat 5'. Meaning it took about 70 seconds
> to write out 158M. Or about 2.2M/s. That's probably not bad. It still locks
> up the system for over a minute though -- which is really undesirable performance
> for interactive use. I'm guessing the vmstat output numbers are showing 4K? 8K?
> blocks? 8K would about make sense for the 2.2M average.

Most likely 4kB blocks. I'd say the numbers are pretty bad...

Jens Axboe

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