Slow on heavy I/O operations.

[Cheffo]

Roman Gorohov. wrote:

-CUT-
> 
> That seems like true, and I forget to mention that 2/3 of swap is
> located at physical disk(da0).
> [idle at hst ~]#swapinfo
> Device          1K-blocks     Used    Avail Capacity  Type
> /dev/da0s1b        524160   463300    60860    88%    Interleaved
> /dev/rvn0b        1048448   578724   469724    55%    Interleaved
> Total             1572608  1042024   530584    66%
> 
> But what I can't understand - why such non-critical(as it seems to me) disk activity,
> cause 100% busyness for disk? Its claim to be 40.000MB/s transfers, but
> sometimes its 100% busy when iostat show only 1 MB/s.
> 
> Regards, Roman.

Imagine 1000 request per second and every request is 1KB,
and compare it with a single request that is 1MB.

In first variant your disk will be 100% busy and in the second 2-3%.
I think you can guess why ?

> 
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-- 
Best Wishes,
Stefan Lambrev
ICQ# 24134177