iostat

[Giada Bonfà]

Hi,
I've this output from the command iostat:

device bps sps msps

c1t2d0 -0 -0.0 1.0
c2t2d0 -0 -0.0 1.0
c8t0d0 -0 -0.0 1.0

Why is there a negative value for bps and sps?
What does it mean? Before the output was:device bps sps msps

c1t2d0 0 0.0 1.0
c2t2d0 0 0.0 1.0
c8t0d0 0 0.0 1.0

Thank you. Bye

[Stefan Farrelly]

Ive tried it on several servers and its always 0 (not -0). Are you using the latest version ?

what /usr/bin/iostat:
$Revision: 80.2.1.5 $
PATCH_11_00: iostat.o 00/07/17

If you read the manpage for iostat you will see that it says its calculations are at best only an approximation - ie. its inaccurate, therefore the negative value is probably the victim of some poor rounding up of a negative value to 0 or simply bad programming. Nothing you can do about it im afraid - but dont rely on stats from iostat as its unreliable. Use something like sar or glance instead.

[Ravi_8]

Hi,
I had checked on several servers,iostat shows always shows +0 values.

could post the o/p from vmstat or sar which gives better results

[Michael Tully]

Why use 'iostat' ? It is old outdated and practically useless with todays external disk arrays.

Your better off using the outputs of glance and measureware which are far more accurate.
If you don't have glance/measureware, then you can install a trial copy from your application CD set for 60 days to try it out.

[Giada Bonfà]

The output of vmstat is in the attachment.
Thank you.