Xen on a second hard drive

[SirLancelot]

I've followed the guide at
http://www.howtoforge.com/debian_etc...ian_repository
and this works perfectly.
I am now installing on a new server. the hard discs on this server are as follows:-
sda is a 250GB sata drive that I shall for now leave unpartitioned and will later be used as a mounted physical drive for one of the domU's.
sdb is a scsi raid1 array that I shall use as the main install drive for xen and the domU images, with 2 partitions "/" and "swap".
Installing debian then selecting (hd1) for grub works fine and the first disc (sda) is ignored by grub and the machine boots correctly. However after xen is installed the machine fails to boot with the message:-
"ALERT! /dev/sdb1 does not exist. Dropping to shell!"
Also none of the other boot options in the grub boot menu work. I am guessing that xen from the repository does not like to be installed on sdb and it is destroying the main partition.
has anyone come accross this issue and is there a way to overcome this so that xen knows that it is being installed on a second hard drive?
Many thanks in advance.
Steve

[SirLancelot]

After searching around it appears that this may be a bug causing the system to time out when trying to detect partitions on a raid or lvm at boot time. This does seem strange as I would have thought that during testing xen would have been tested on a raid set.
Would anyone have any ideas for a fix for this, or am I looking in the wrong direction?
Thanks

[SirLancelot]

Update
this error still persists but if I reboot several times the system will boot up correctly.
There seems to be an issue with it timming out sometimes when trying to boot from a hardware RAID1 set. I can live with this for the moment as once configured it will remain up, with just the occasional reboot.
If someone has an aswer for this it would be helpfull so i dont have to go into the server room and stand around and watch it boot up on the rack console.
Many thanks.

[falko]

What's in /boot/grub/menu.lst and /etc/fstab? What's the output of

fdisk -l

?

Are there any errors in the output of

dmesg

?

[SirLancelot]

Hi Falko,
cheers for your assistance with this.

Originally Posted by falko

What's in /boot/grub/menu.lst and /etc/fstab? What's the output of

fdisk -l

?
Are there any errors in the output of

dmesg

?

/boot/grub/menu.lst is:-

# menu.lst - See: grub(8), info grub, update-grub(8)
# grub-install(8), grub-floppy(8),
# grub-md5-crypt, /usr/share/doc/grub
# and /usr/share/doc/grub-doc/.

## default num
# Set the default entry to the entry number NUM. Numbering starts from 0, and
# the entry number 0 is the default if the command is not used.
#
# You can specify 'saved' instead of a number. In this case, the default entry
# is the entry saved with the command 'savedefault'.
# WARNING: If you are using dmraid do not change this entry to 'saved' or your
# array will desync and will not let you boot your system.
default 0

## timeout sec
# Set a timeout, in SEC seconds, before automatically booting the default entry
# (normally the first entry defined).
timeout 5

# Pretty colours
color cyan/blue white/blue

title Xen 3.0.3-1-i386-pae / Debian GNU/Linux, kernel 2.6.18-6-xen-vserver-686
root (hd1,0)
kernel /boot/xen-3.0.3-1-i386-pae.gz
module /boot/vmlinuz-2.6.18-6-xen-vserver-686 root=/dev/sdb1 ro console=tty0
module /boot/initrd.img-2.6.18-6-xen-vserver-686
savedefault

title Debian GNU/Linux, kernel 2.6.18-6-486
root (hd1,0)
kernel /boot/vmlinuz-2.6.18-6-486 root=/dev/sdb1 ro
initrd /boot/initrd.img-2.6.18-6-486
savedefault

title Debian GNU/Linux, kernel 2.6.18-6-486 (single-user mode)
root (hd1,0)
kernel /boot/vmlinuz-2.6.18-6-486 root=/dev/sdb1 ro single
initrd /boot/initrd.img-2.6.18-6-486
savedefault

### END DEBIAN AUTOMAGIC KERNELS LIST


/etc/fstab is:-

proc /proc proc defaults 0 0
/dev/sdb1 / ext3 defaults,errors=remount-ro 0 1
/dev/sdb5 none swap sw 0 0
/dev/hda /media/cdrom0 udf,iso9660 user,noauto 0 0


fdisk -l produces:-

Disk /dev/sda: 250.0 GB, 250059350016 bytes
255 heads, 63 sectors/track, 30401 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

Device Boot Start End Blocks Id System
/dev/sda1 1 30401 244196001 83 Linux

Disk /dev/sdb: 18.2 GB, 18208260096 bytes
255 heads, 63 sectors/track, 2213 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

Device Boot Start End Blocks Id System
/dev/sdb1 * 1 2115 16988706 83 Linux
/dev/sdb2 2116 2213 787185 5 Extended
/dev/sdb5 2116 2213 787153+ 82 Linux swap / Solaris

I found the following errors when executing dmesg:-

ACPI Error (psargs-0355): [Z00Q] Namespace lookup failure, AE_NOT_FOUND
ACPI Error (psparse-0537): Method parse/execution failed [\_SB_.PCI0.ISA_.SIO_.COM1._STA] (Node c1b4e6a8), AE_NOT_FOUND
ACPI Error (psargs-0355): [Z00Q] Namespace lookup failure, AE_NOT_FOUND
ACPI Error (psparse-0537): Method parse/execution failed [\_SB_.PCI0.ISA_.SIO_.COM2._STA] (Node c1b4e5b8), AE_NOT_FOUND
ACPI Error (psargs-0355): [Z00Q] Namespace lookup failure, AE_NOT_FOUND
ACPI Error (psparse-0537): Method parse/execution failed [\_SB_.PCI0.ISA_.SIO_.LPT_._STA] (Node c1b4e478), AE_NOT_FOUND
Linux Plug and Play Support v0.97 (c) Adam Belay
pnp: PnP ACPI init
ACPI Error (psargs-0355): [Z00Q] Namespace lookup failure, AE_NOT_FOUND
ACPI Error (psparse-0537): Method parse/execution failed [\_SB_.PCI0.ISA_.SIO_.COM1._STA] (Node c1b4e6a8), AE_NOT_FOUND
ACPI Error (psargs-0355): [Z00Q] Namespace lookup failure, AE_NOT_FOUND
ACPI Error (psparse-0537): Method parse/execution failed [\_SB_.PCI0.ISA_.SIO_.COM2._STA] (Node c1b4e5b8), AE_NOT_FOUND
ACPI Error (psargs-0355): [Z00Q] Namespace lookup failure, AE_NOT_FOUND
ACPI Error (psparse-0537): Method parse/execution failed [\_SB_.PCI0.ISA_.SIO_.LPT_._STA] (Node c1b4e478), AE_NOT_FOUND
pnp: PnP ACPI: found 10 devices

[jeffd]

I've had this problem before on some dells, the installer would see the cdrom as /dev/sda and the first HD as /dev/sdb/ and I would have to edit the grub boot line and swtich out sdb with sda then make that change in /boot/grub/menu.lst and in /etc/fstab

One thing you could do to fix this is to use UUIDs for your partions. When you get the system up run:

blkid

This should give you a list of IDs and what partition they map to. You can then use that UUID in your /boot/grub/menu.lst in place of the /dev/sdxx like so:

title		Debian GNU/Linux, kernel 2.6.26-1-686-bigmem
root		(hd0,0)
kernel		/vmlinuz-2.6.26-1-686-bigmem root=UUID=84f7fcdb-1172-42aa-bf7e-8ba09d4c8efe ro quiet
initrd		/initrd.img-2.6.26-1-686-bigmem

Of course,use the UUID you get from the blkid commnad. You can use the same method in /etc/fstab as well.