RE: New 270.

[John Ross <jross-ml@xxxxxxxxxxxxxxx>]

I was told last week by a business partner, not to go over double the size
of your smallest dive in your system, so if you have a 4 do not go over an
8.  He tried to explain why but I really did not understand it. Something
about it would get more reads on the smaller drive.

Would it matter how you let the system spread the data? If you just put
another drive in and do not force it to spread the data on the system, it
seams like the new data would be put on the new drive and might get more
reads then older data, at least for a while. If you are letting the system
spread the data (Not forcing it) does it only put writes on the new drive
or will it force data that it should only be reading to be moved. Does the
OS try to stay on the first drive(s)? (I think in my 38 days I heard it
did) IF so with 8's it might spread over 2 drives with 17's it could all
end up on the first drive. And it seams the OS would be used a lot. I have
used WRKDSKSTS for 15 min and the number 1 disk is 1st or second for
percent busy, but only by 1%.

Is there a link anywhere that explains how IBM spreads the Data?

John Ross
www.opensource400.org


> > Subject: Re: New 270.
> >
> > Last year, I made the move from 6- 8 GB drives to 6-17 GB, and
>performance
> > suffered considerably.
> >
> > Al