Resolved (Re: [Beowulf] Weird CentOS Install Problem)

Jon Forrest jlforrest at berkeley.edu
Mon Aug 11 17:18:23 EDT 2008


As several people suggested, the weird CentOS install
problem I described last week was solved by using a separate
small /boot partition. I used a 100MB partition.

On the other hand, I do not understand why this made
a difference. I originally had a root partition that
started on cylinder 1, as shown by the fdisk program.
I now have a /boot partition that starts on cylinder 1.
The only difference is the ending cylinder number.
I don't recall what it was originally but it was
clearly greater than 1024. Now it's 13. I had no
idea that the ending cylinder number made any difference
as long as the files in /boot were all located in cylinder
numbers <= 1024.

Of course, cylinder numbers and other disk geometry measurements
are completely virtual in a hardware RAID since the controller
translates from the ideal disk the OS sees to the physical
locations on the real disks.

The thought crossed my mind that maybe the files in /boot,
particularly vmlinuz, just happened to end up on cylinders
 > 1024. If so, that might be an explanation for what happened.

Be that as it may, I consider this a bug in the 3ware BIOS.
Every modern motherboard BIOS I've seen in the last 5 years,
at least, has no problem booting from gigantic root partitions.
Why should the 3ware BIOS be any different? I've opened
a case with them to try to get to the bottom of this.

I appreciate all the comments I received about this problem.
I hope that other people who have this problem find this
discussion via Google so that they can save themselves some time.

Cordially,
-- 
Jon Forrest
Research Computing Support
College of Chemistry
173 Tan Hall
University of California Berkeley
Berkeley, CA
94720-1460
510-643-1032
jlforrest at berkeley.edu
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