Ubuntu Server 12.04 - SAS system drive, and won't boot with more than two SATA drives

munaye · 11-01-2013, 04:09 PM

Hello Linux World! Firstly, I did my best to choose what seemed the best forum for this post. Apologies if another forum would be a better placement. Also, whilst composing the post below, I've interrupted myself with several web searches and suspect the problem I describe may stem from trying to mix various drive types - SAS and SATA - in a Linux system. In any case, here's the deal:

I recently installed Ubuntu Server 12.04.3 LTS to an HP XW8400 workstation. The system drive is SAS. I've successfully added two SATA drives to the system, and been able to create shares from these two (NTFS formatted) SATA drives, and successfully share to a Windows network using Samba. Huzzah.

Problem is, things go wonky when I plug in a third (also NTFS) SATA drive. The system won't boot to Ubuntu with the third SATA drive attached. I was able to (carefully. . .) attach and mount the third SATA drive when the system was booted. However, shortly after that, the system crashed. Sorry, can't remember the error messages.

I don't believe this is a hardware problem, for several reasons, and to list two:

1. Before converting this box to Ubuntu, it was running Windows Server with the same four drives (SAS as system drive, and the three SATA drives) attached and working.

2. With only two SATA drives attached, I can boot with any combination among the three drives. That is, I can boot with SATA drive A and SATA drive B attached, as well as drives A & C, and B & C. I've also swapped the SATA cables around and tried different combinations of SATA ports on the motherboard, as well as trying to boot both with and without the(again, SATA)optical drive attached. Doesn't make a difference.

So what it comes down to is that I can't boot or use the system with more than two SATA drives attached.

One more thing, probably obvious, but none of the drives are in RAID.

Thanks in advance and, hey, even though things aren't going as planned, I'm as excited about finally moving into this Linux thing, as when I got my first Commodore 64!

widget · 11-02-2013, 01:10 PM

I believe that your problem is the drive designation.

Assuming you have a monitor on this box, boot a Live CD and see what your drives are designated as. I suspect the drive that you installed on, sda, is no longer seen as sda by the system. This seems to be a problem with some controllers due to support for hot plugging.

When you have the 3 extra drives all running it could well be that the drive with you system on it is being seen as sdb, sdc or sdd. As grub is calling for, I assume, partition sda1 for your Ubuntu install this would be a problem.

The live session should give you any such information you need to find the correct drive.

Running;

Code:

sudo fdisk -l

should show where the Ubuntu partition is as seen by your system

Chrooting to the Ubuntu install and running;

Code:

sudo update-grub

and

Code:

sudo grub-install /dev/sdx

where x is the drive designation should have you booting again. And should continue to boot correctly.

munaye · 11-04-2013, 02:49 PM

Widget, thanks for the reply. Yes, apparently on this box, SAS drives are assigned letters after SATA drives. So at boot time, with three SATA drives + the one SAS drive attached, the SAS drive with the Ubuntu Server installation is being assigned /dev/sdd.

I understand your instructions in principle, but I can't implement them while booted into the live cd, as I don't yet understand the chroot syntax. For instance, I'm entering,

Code:

chroot /dev/sdd

but the result is

Code:

chroot: cannot change root directory to /dev/sdd: Not a directory

Also tried adding specifying the partition numbers (e.g., /dev/sdd1) but with the same result. Have also tried mounting the drive and chroot-ing using the mount name, but that only yields a variation on the same error. (". . . No such file or directory")

Sorry to ask, but I've already spent more time than I can spare today researching chroot. Please be specific about how to use chroot in this context.

Thanks!

widget · 11-04-2013, 04:22 PM

You should probably check this;

Code:

info coreutils 'chroot invocation'

for some information on chroot.

You need to have a mount point for your drive;

Code:

mkdir /mnt/wtf

Where "wtf is what ever you want to name the mount point in the /mnt directory (usually used to mount things but you could use any directory you want).
Mount the drive in that directory;

Code:

mount /dev/sdd /mnt/wtf

The easiest thing to do would be to edit this list of commands to fit your box;

Code:

mkdir /mnt/Jessie-root
mount /dev/sda10 /mnt/Jessie-root/
mount -o bind /proc /mnt/Jessie-root/proc
mount -o bind /dev /mnt/Jessie-root/dev
mount -o bind /dev/pts /mnt/Jessie-root/dev/pts
mount -o bind /sys /mnt/Jessie-root/sys
cp /etc/resolv.conf /mnt/Jessie-root/etc/resolve.conf
chroot /mnt/Jessie-root /bin/bash

That is what I use to chroot into that particular / partition to do what ever needs done.

For grub you will want to;

Code:

update-grub

So that all the menu entries are aimed at the correct drive.
Then;

Code:

grub-install /dev/sdd

I do not use sudo so should point out that all the above commands are done at the root (#) prompt.