On Oct 8, 2007, at 10:12 AM, Frans Pop wrote:
Adding the dasd= boot parameter did not help - it seems to be ignored in our initrds; changing /etc/fstab to use /dev/disk/by-path devices consistentlydoes result in a correct boot. I'll consult with other Debian people how we want to resolve this.
I think /dev/disk/by-path is probably the best choice for an s390 system. Here's why:
Most s390/zSeries users run either under z/VM or Hercules; in either case, they have a virtualization environment layer of some kind available to them. Because of this, it's really easy to clone disks via a simple copy (either at the track level in z/VM with DDR or with cp in hercules) and very common to make rescue systems by simply attaching another guest's disks to a still-good guest.
For these reasons, device detection order is not a good idea, and disk UUID or label are also poor choices since cloned disk devices are so common. On the other hand, most organizations have at least an informal standard for how to map disks. For example, we do the following: 150 is the IPL device (and sometimes all of /); 151 is usually swap; 152-15F are system disks, 160-16F are disks for users or applications. At least in the environments in which I work and consult, device addressing is a more reliable guide to what disk should be mounted where than any of the other options.
Adam