problems with new kernels on redhat 6.0

problems with new kernels on redhat 6.0

Post by Johan Kullsta » Sat, 07 Aug 1999 04:00:00

i am having trouble with new kernels on redhat 6.0.
my machine is a alr revolution quad6 (quad ppro-200) with 256M ram,
adaptec 2940uw scsi pci adapter and a 9.1G sca scsi fujitsu drive in
the swap bay.

i've been using fresh egcs and binutils as they've become available.
unless otherwise noted, all kernels are smp.  disk i/o speed
measurements are done by bonnie.

redhat 5.2 with glibc-2.0 and glibc-2.1 worked fine with all kernels
from 2.1.124 through 2.2.9.

at that point i installed redhat 6.0.  the stock redhat kernel works
fine.  i wanted to compile my own kernel.  i compile 2.2.5 with
aic7xxxx built into the monolith.  i have only one module tulip.o (and
dummy.o but that isn't loaded as far as i can tell).  since i put the
scsi driver in the kernel, i am not using initrd.  my own compiled
2.2.5 kernel works fine.  (after nuking ifup-aliases to shut up
kvetches about not finding lo:1-50 and eth0:1-50)

i upgrade to 2.2.6 and things are still good.

i go to 2.2.7 and my disk access gets *very slow*.  running bonnie
shows that char-wise read/write is about 40K/sec (down from 3000K/sec
for working kernel).  interestingly, block read/write is nearly the
same as a good kernel.  there isn't any disk data corruption, just
slow access.  disk access is similarly slow for all of 2.2.8, 2.2.9
and 2.2.10.

i note that the aic7xxx driver is *identitical* in both 2.2.6 and
2.2.7.  very little changes wrt smp and disk or file system occur
between these versions.

dmesg looks the same for all the kernels.  while some version number
change, there are no errors or warnings printed.

i tried out 2.2.10 in uniprocessor and get good disk performance.

i am suspicious of an irq conflict (this can cause slow modems) since
each scsi adapter and disk access is being punished by a fixed
amount (independent on the size of the data block being moved).

remember, kernel 2.2.7 and 2.2.9 worked fine before (with redhat 5.2
using both glibc-2.0 and glibc-2.1).  i suspect something wacky is
happening during the boot sequence (since i can't figure out anything
else to blame).

watching the boot, i notice a slow down right after it talks about
entering run-level 3 and the init script starts its `daemon loading
ok' spew.

has anyone else got this or similar problem?  has anyone managed to
fix it?

johan kullstam


1. Problems with installing new harddisk on RedHat Linux 6.0


I recently bought a new hard disk (Seagate ST336705LW, LVD SCSI, 36 GB). My
system consists already of 2 9GB IBM LVD Disks, the first with Windows NT,
the second with RedHat Linux 6.0 (I know I should update). The Disks are on
a Adaptec AIC 7890 controller (aic7xxx module in Linux kernel). I use LILO
to boot to Windows or Linux.
I installed the new disk and then booted into Windows, made a 24 GB
partition and fomatted it. No problems there.
Then I rebooted into Linux, but when it came to recognize the new disk all I
got were timeouts on the SCSI bus. I had to physically disconnect the new
disk, then i could boot into Linux again. After searching a bit I thought it
might be the aic7xxx driver in Linux, because in Windows it worked
perfectly, RedHat was updated some times already, and the disk i a fairly
new type. I then tried to install a new version of this driver, but I
failed. What is left that i can't boot into Linux anymore, even if the new
disk is disconnected. I can boot with the rescue disk, and mount all the
partitions on the Linux disk. What I get when I try to but the normal way is
an error message from kmod, that it could not execute /sbin/modprobe -s -k
<something>, with error number 2, and that it xould not mount root partition
on 08:17 (whatever that means).

So thats the current state of my box. I'm interested what the kmod error
message is, and how I can fix it, if possible.
I will try to update Linux to RedHat 7.0 . Maybe that helps.

Thanks for your help


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