Tracking if disk is busy

[Alex Zbyslaw]

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?

You can use plain old vmstat to see blocks being transferred.

--Alex