problems with Xraid and RHEL 4

problems with Xraid and RHEL 4

Post by Mark Parke » Fri, 08 Apr 2005 06:38:00


Hi all,
I've got a problem getting redhat to recognize my 2.2TB scsi device.
It's 1/2 of a 5.4 TB apple Xraid. I've worked with it a bit and found
that when the size of the scsi device falls below 2TB (I'm working with
400MB drives here so don't quote me of the size boundary) that fdisk
will allow me to create a primary partition the uses all the cylinders.
When the size goes above 2TB, fdisk will only allow me about 10% of the
total cylinders it reports. I even tried faking out fdisk with a
different block size and it then let me set the number of cylinders to
the last cylinder. However, it will then still report only a smidge of
the true amount of space later on.
I've sliced the 2.2TB device into 2 1.1TB devices and used mdadm to
create a 2.2TB slice so I know that at least works. I just hate to have
software doing the job of hardware.
If anybody knows why fdisk won't let me create a full partition that'd
be nice.
Here are some details:

IBM eserver 326 dual opterons w/ mirrored 80GB SATA drives.
RHEL 4 AS.
Apple Fibre Channel pci-x cards.
Apple 5.6TiB Xraid.

Example fdisk madness (as you'll see, fdisk won't let me set the number
of cylinders to the total even though it reports this number):

------------ Begin madness ---------------
[root@snow /]# fdisk /dev/sde

The number of cylinders for this disk is set to 291843.
There is nothing wrong with that, but this is larger than 1024,
and could in certain setups cause problems with:
1) software that runs at boot time (e.g., old versions of LILO)
2) booting and partitioning software from other OSs
(e.g., DOS FDISK, OS/2 FDISK)

Command (m for help): p

Disk /dev/sde: 2400.4 GB, 2400492453888 bytes
255 heads, 63 sectors/track, 291843 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

Device Boot Start End Blocks Id System

Command (m for help): n
Command action
e extended
p primary partition (1-4)
p
Partition number (1-4): 1
First cylinder (1-24494, default 1): 1
Last cylinder or +size or +sizeM or +sizeK (1-24494, default 24494): 291842
Value out of range.
Last cylinder or +size or +sizeM or +sizeK (1-24494, default 24494):
Using default value 24494

Command (m for help): p

Disk /dev/sde: 2400.4 GB, 2400492453888 bytes
255 heads, 63 sectors/track, 291843 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

Device Boot Start End Blocks Id System
/dev/sde1 1 24494 196745218 83 Linux

Command (m for help): ^C

------------ Begin madness ---------------

Thanks for any help you can propose.

-Mark