Disk device relabeling problems

Disk device relabeling problems

Post by Seth Maso » Mon, 31 May 1999 04:00:00

                    Redhat 6.0 with kernel 2.2.8 on an HP LH3 (pII,
128MB Ram).
                    Adapter 2944-uw scsi controller.
                    If I access 4 scsi disks which are in the form
(channel,target, lun)= cxtyLz:
                    c0t0L3 = /dev/sda
                    c0t0L4 = /dev/sdb
                    c0t0L5 = /dev/sdc

                    However, if I add another scsi device and set it as
C0T0L2 the next time I reboot the
                    system the device assignments are changed. This
results in the following device
                    c0t0L3 = /dev/sda
                    c0t0L3 = /dev/sdb
                    c0t0L4 = /dev/sdc
                    c0t0L5 = /dev/sdd

                    If in my /etc/fstab I define /dev/sdc (c0t0l5)to be
mounted at a certain location, it in
                    turn mounts /dev/sdd (c0t0l5) which is the new
(after adding c0t0L3) /dev/sdc.

                    I am looking for a solution to the problem of adding
devices which are at a earlier
                    scan order (lower channel,target,lun address) than
other devices and having those
                    new devices change the /dev/sdx assignments.



1. SCO5: Adding third SCSI disk, 2nd disk devices go away

Hardware: Pentium 90, Adaptec 2940 (ID=7), Seagate 2GB SCSI disk (ID=1),
Seagate 1GB (ID=0)  SCSI disk and a Fujitsu 1GB SCSI disk (ID=6) ....
there is an HP DAT (ID=3) and a QIC-525 (ID=2) as well as a CD ROM drive
(ID=5).  32MB RAM. Also an ISA NIC.

OS: SCO5 OSE with the 5.0.0d patch installed.

When adding a third disk to the alad adapter using the following
technique .... (see detail) ... I end up with /dev/hd01 through /dev/hd0d
devices for the boot drive on ID=0 and /dev/hd10 through /dev/hd1d for the
new third drive on ID=6.  Before the process started, the /dev/hd10
through /dev/hd1d devices pointed to the second disk on ID=1.  There were
*no* /dev/hd2* devices at all!

I can "mv" the devices that were created to /dev/hd20 through /dev/hd2d
and re-make the original /dev/hd1* devices with "mknod" in order to patch
the problem, but if I relink I have to do it again as the devices are
remade incorrectly again. (I had to make the /dev/rhd* devices also).

The system is running fine with these manual "mknod" adjustments.

Has anyone else run into this?  I can recreate the problem on different
servers .... can you recreate this?  Can it be explained?  Is my procedure
incorrect ... etcetera

The procedure I used to add the third disk was to:
"mkdev hd" after configuring and installing the drive as ID=6 (4 is the
only other ID left).  I chose the default "alad" adapter 0, SCSI Bus 0, ID
6, LUN 0.  After relinking, I re-ran "mkdev hd" and initialized the disk
w/fdisk and partitioned w/ divvy.  When I went to divvy the second drive
using "divvy /dev/hd10" I got the partition table I just created on the
new third drive.  I checked /dev and found the above referenced problem
with the /dev entries.  I could still fsck and mount the filesystems on
the second drive, just could not divvy the disk.

(extra info)
I installed a second Adaptec and moved the third drive to it under ID=0 to
test the theory that SCO might have trouble with SCSI disks on ID's other
than 0 and 1).  The same symptoms occur.

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