On Monday March 10, keld@xxxxxxxx wrote: > On Mon, Mar 10, 2008 at 10:01:50AM +1100, Neil Brown wrote: > > On Saturday March 8, keld@xxxxxxxx wrote: > > > I want to assemble the root partition automatically, without having > > > a configuration file. Is that possible? > > > > > > mdadm -A --scan > > > > > > does seem to require a configuration file. > > > > > > On the other hand, I think all info needed is available in the super > > > blocks, and a traversal of the partitions present on the system (ala > > > fdisk -l) could give consistent naming - there seems to be no /dev/md > > > association available in the superblock. > > > > The information that is not present in the super blocks is which > > array you want to assemble. > > Yse, that is evident. > > > This becomes particularly important if you move some drives from one > > machine to another. > > Moving a disk from one machine to another is not the common thing with > raids. This is only done in special cases, and not prat of ordinary > operations. I absolutely agree. However the time when you do it you are quite possibly trying to get something that was broken working again. And so you don't want any surprises. So I encourage configurations where moving devices around will not cause unpleasant surprises. Tagging all arrays with the host name helps remove these surprises. > > > For that reason mdadm knows about a "homehost". You can tag each > > array with a hint about what host it expects to be assembled on. > > If you run > > > > mdadm -As --homehost=`hostname` > > > > then it will auto-assemble any arrays for the current host. > > If you arrays haven't been tagged for at particular host, then > > > > mdadm -As --homehost=`hostname` --auto-update-homehost > > > > will automatically tag everything that is found for the current host. > > This is not something that should be done automatically, but it OK to > > do one when you know you haven't done anything interesting with > > devices. > > Hmm, I am still looking for a way to boot a linúx raid as root. Look at README.initramfs in the mdadm release. It might not answer all your questions, but I describes in general how it should work, and provides a simple sample you could build on. NeilBrown -- To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
