We are trying to optimize disk performance, and we came up with this
idea of achieving a rudimentry disk striping using OnLine mirroring.

Currently we have two 1.5 GB disks, one of which has 3 Primary chunks
and the other one has three Mirror chunks.  During execution of
large "select" queries the drive containing Primary chunks has
utilization of 100% whereas the other drive is idle.  That means that
Informix doesn't use Mirror chunks for reading (this is probably burried
somewhere in the manual but I didn't see it in my first glance).

So the idea is to make one of the chunk (or two if we divide the dbspace into
four chunks) on the second drive a primary chunk and change the corresponding
chunk on the first drive as Mirror chunk.  So now, during a read both the
drives have teh chance to participate.  This should ideally improve
the performance during reads.

Now, the question is has anyone tried this before or are there any
potential problems/issues with this approach?

Thanks for any responses.

---------------
Yogen Sanghani

(212)972-4266

I received four responses , the summary is that it is a good, standard way
of optimizing disk performance.  One of the response was that Informix 6.0
is going to be using mirror chunks for reading.  Thanks for the responses.

: ---------------
: Yogen Sanghani

: (212)972-4266