%wio from sar

Folks,
I understand that %wio is an idle statistic (Kevin Closson had confirmed it for me). I use this statistic to get a feel whether the system is spending a lot of time waiting for IO or not. I have seen in the past that each time we had some I/O related issue where the system was processing I/Os slowly, the statistic was showing high values. Sun is telling me that this statistic should not be relied on. I need an opinion whether this statistic should be considered when diagnosing IO issues at the server level or not.

Thanks
Amir

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