I run into a strange problem when I upgraded some VMs from Debian Etch to Lenny. I’m using VMware Fusion on my MacBook Pro and VMware Server on my local Debian Server. Upgrading VMs hosted by the VMware Server ended in System boot hangs “Waiting for root file system”. Upgrading nearly the same Etch VMs hosted by VMware Fusion did not fail.

According to Debians Upgrade instruction and it’s “How to recover” section, the problem can be caused by new naming conventions for IDE disks.

This problem can occur when the upgrade of the kernel introduces the use of the new generation of IDE drivers. The IDE disk naming convention for the old drivers was hda, hdb, hdc, hdd. The new drivers will name the same disks respectively sda, sdb, sdc, sdd. The problem appears when the upgrade does not generate a new /boot/grub/menu.lst file to take the new naming convention into account. During the boot, Grub will pass a system root partition to the kernel that the kernel doesn’t find.

This seems like to be very common reason for these “Waiting for root file system” troubles that many faces now when upgrading to Lenny. But in my case I allready had the new sda* names in the grub/menu.lst and /etc/fstab. The “solution to recover” did not work.

The virtual lenny server with the new kernel images that fails to boot was hosted by VMWare Server 1.0.3. For a nearly the same upgrade process (etch to lenny) hosted on FMWare fusion 2.0.2, I did not have these problems.

Solution: My VMWare Server 1.0.3 was out of date and had a known vmware bug that caused this error. Upgrading to the latest version (now 1.0.8) solved the problem.