[ On Monday, October 28, 2002 at 19:37:22 (+1100), matthew green wrote: ]
> Subject: separate read vs. write disk stats.
>
> 
> i've implemented separate read/write statistics for disks.  the kernel
> portion is just changing disk_unbusy() to take a direction parameter,
> adjusting struct disk to have the new parts and updating the sysctl
> to deal with this(1).

Yes!  Thank you very much!

> one could change the current default output to include both read/write
> stats but i think that might break someone's script and it also uses
> more of the already precious screen (line) real estate, so i don't like
> that option a whole lot.

I don't think you have to worry too much about just changing the default
presentation in the various systat "screens".

> one option would be to add the stats to iostat's -x ('extended') output,
> add a -x flag to vmstat to enable it, and some other option to systat.
> (for systat, i currently have code that does this with ":all" and ":rw"
> commands to switch between them, default of "all".  alternate suggestions
> on these names welcome.)  i believe that solaris shows read & write
> separately with 'iostat -x'.

Yes, Solaris extended output looks like a good one to emulate:

13:25 [131] $ uname -srm                                           
SunOS 5.6 sun4m
13:25 [132] $ iostat -x                                            
                               extended device statistics
device    r/s  w/s   kr/s   kw/s wait actv  svc_t  %w  %b 
sd0       1.0  0.2    4.3    3.2  0.0  0.0   16.9   0   1 
sd1       1.0  2.5   40.9   87.2  0.0  0.1   18.3   0   4 
sd2       1.2  6.6   42.5  126.1  0.0  0.2   20.9   0   8 
nfs1      0.0  0.0    0.0    0.0  0.0  0.0    0.0   0   0 

-- 
								Greg A. Woods

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