Re: Hardware/OS recommendations for large databases (

William Yu wrote:
> Alan Stange wrote:
>> Luke Lonergan wrote:
>>> The "aka iowait" is the problem here - iowait is not idle (otherwise it
>>> would be in the "idle" column).
>>>
>>> Iowait is time spent waiting on blocking io calls. As another poster
>>> pointed out, you have a two CPU system, and during your scan, as
>>
>> iowait time is idle time. Period. This point has been debated
>> endlessly for Solaris and other OS's as well.
>
> I'm sure the the theory is nice but here's my experience with iowait
> just a minute ago. I run Linux/XFce as my desktop -- decided I wanted
> to lookup some stuff in Wikipedia under Mozilla and my computer system
> became completely unusable for nearly a minute while who knows what
> Mozilla was doing. (Probably loading all the language packs.) I could
> not even switch to IRC (already loaded) to chat with other people
> while Mozilla was chewing up all my disk I/O.
>
> So I went to another computer, connected to mine remotely (slow...)
> and checked top. 90% in the "wa" column which I assume is the iowait
> column. It may be idle in theory but it's not a very useful idle --
> wasn't able to switch to any programs already running, couldn't click
> on the XFce launchbar to run any new programs.

So, you have a sucky computer. I'm sorry, but iowait is still idle
time, whether you believe it or not.

-- Alan