Re: Hardware/OS recommendations for large databases (

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.