On Mon, Sep 04, 2017 at 12:22:33PM +1000, NeilBrown wrote: > On Fri, Sep 01 2017, Michał Mirosław wrote: > > > On Fri, Sep 01, 2017 at 10:07:29AM +1000, NeilBrown wrote: > >> On Wed, Aug 30 2017, Michał Mirosław wrote: > >> > Allow changing active array's set_name. This is the only way to > >> > safely update superblock on an array which carries a mounted fs. > >> > >> Do you really need to change the set_name of an active array? > >> > >> The name is only used when the array is actived, so wait until the next > >> time the array is stopped, and change the name then. > >> > >> You can boot with a rescue CD or similar and use "--assemble > >> --update=name", or with a bit of effort you could get the normal boot > >> sequence to change the name. > >> > >> I wouldn't object to adding something to mdadm so that it would read > >> something from mdadm.conf, and update the set name at boot time. > >> > >> What is the underlying problem that you are trying to solve here? > > > > I had to fix /dev/md* naming on a system with no physical access. > > > > The problem was that despite matching mdadm.conf entries, arrays started > > with random 127-i indexes (because superblocks' set_names didn't match > > hostname, I guess). > > That's odd. If an array is listed in mdadm.conf, that is enough to tell > mdadm that it is "local" so that it doesn't need the hostname to match. > Can you show me exactly what was in your mdadm.conf? This is what was I had when it would reassign arrays on boot. System hostname is 'rere' - it was renamed some time after creating arrays. ---8<--- HOMEHOST <system> MAILADDR root ARRAY /dev/md/0 metadata=1.2 UUID=d5ea39a9:5ec27c36:c83296d4:70f879d4 name=rere2:0 ARRAY /dev/md/1 metadata=1.2 UUID=9bf69b92:2e7ba905:5f959c09:c8fecb99 name=rere2:1 ---8<--- I don't have old versions of mdadm.conf, so had to recreate this one. IIRC I verified UUIDs back then, but don't remember whether I modified names or not. Thinking of it, how would mdadm behave if it had matching UUIDs and mismatching array names in mdadm.conf? Best Regards, Michał Mirosław -- 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
