2013/7/2 Grant Edwards <[email protected]> > On 2013-07-01, Grant Edwards <[email protected]> wrote: > > > I've just recently run into a problem where sometimes when a machine > > boots, the kernel can't find init. This appears to be because my grub > > configuration line says "root=/dev/sda5" and _sometimes_ the drive > > that contains my root partition is sdb instead of sda. AFAICT, for the > > past 30 years the linux kernel was 100% consistent in the order that > > hard drives were labelled -- but recently that has seems to have > > changed. > > I still haven't figured out why my drives suddenly started getting > discovered in varying orders. I think that the SATA drives are always > in the same order with respect to each other, but sometimes the > external firewire drive gets discovered before the SATA drives and > sometimes after the SATA drives. > > It looks like my options are: > > 1) Keep hitting the reset button until it works. > > 2) Unplug or power down the firewire drive when booting. > > 3) Set up an initrd for the sole purpose of finding the actual root > parition via filesystem label. [I find this idea rather offensive.] > > 4) Build the firewire drive as a module instead of building it into > the kernel. That would delay the discovery of the firewire drive > until after root has been mounted. > > 5) For the drive with the root parition on it switch from a DOS > parition table to a GPT partition table and use the > root=PARTUUID=<whatever> kernel option. > > You don't need to switch to GPT for that. I have a DOS partitioned disk and "blkid" prints the LABEL and UUID for each partition.
> 6) Fix the kernel so it can find root by looking at filesystem > labels. > > Number 6 (fixing the kernel) is The Right Thing To Do(tm), but it's a > bit out of scope for the momement. The "early code" in the kernel > obviously knows how to read partition tables and also knows about the > relevent file system, so I'm a bit baffled why it can't look at the > file system label. > > Changing the firewire driver to be a module is probably the simplest > solution, but it's a kludgy work-around for what is, in my opinion, a > kernel bug: if you are going to require people to specify an absolute > disk drive index for the root partition, then you'd better index > drives in a consistent order from one boot to the next. > > Switching to a GPT partition table sounds like the cleanest solution, > but I need to figure out if the grub (legacy) ebuild includes GPT > support or not. I know it's supported by grub2, but I don't really > feel like switching to grub2 ATM. > > -- > Grant Edwards grant.b.edwards Yow! But was he mature > at enough last night at the > gmail.com lesbian masquerade? > > > -- Mit freundlichen Grüßen / Best regards Randolph Maaßen
