Tracking if disk is busy

[Nikos Vassiliadis]

On Friday 23 June 2006 01:12, Matt Ruzicka wrote:
> We've got a couple servers that appear to have particularly busy disks and
> I was trying to determine if there is a way to more easily poll this data
> for tracking.
>
> I'm not sure if this is one of those can't see the forest for the trees
> issues or not, but the only means that I am familiar with to see the
> percentage of time the disk is busy is to run 'systat -vmstat'.  I was
> hoping for something more concise that I could run periodically and maybe
> even graph (realizing that watching this might well distort the results).
>
> It appears that iostat on Solaris gives this information, but I can't seem
> to mimic this functionality with FreeBSD.
>
> Are there other ways in FreeBSD to pull the percentage of time the disk is
> busy?
>

gstat gives percentage load per (device|slice|partition) which is what I think 
you need. but it's written for interactive use, it issues commands to the
terminal so you cannot have its output to file...