On Fri, 10 Sep 2010 19:36:18 -0400 Mike Hartman <mike@xxxxxxxxxxxxxxxxxxxx> wrote: > >On Fri, Sep 10, 2010 at 7:07 PM, Neil Brown <neilb@xxxxxxx> wrote: > > On Fri, 10 Sep 2010 18:45:54 -0400 > > Mike Hartman <mike@xxxxxxxxxxxxxxxxxxxx> wrote: > > > >> On Fri, Sep 10, 2010 at 6:37 PM, Neil Brown <neilb@xxxxxxx> wrote: > >> > On Sat, 11 Sep 2010 00:28:14 +0200 > >> > Wolfgang Denk <wd@xxxxxxx> wrote: > >> > > >> >> Dear Mike Hartman, > >> >> > >> >> In message <AANLkTim9TnyTGMWnRr65SrmJDrLN=Maua_QnVLLDerwS@xxxxxxxxxxxxxx> you wrote: > >> >> > This is unrelated to my other RAID thread, but I discovered this issue > >> >> > when I was forced to hard restart due to the other one. > >> >> > > >> >> > My main raid (md0) is a RAID 5 composite that looks like this: > >> >> > > >> >> > - partition on hard drive A (1.5TB) > >> >> > - partition on hard drive B (1.5TB) > >> >> > - partition on hard drive C (1.5TB) > >> >> > - partition on RAID 1 (md1) (1.5TB) > >> >> > >> >> I guess this is a typo and you mean RAID 0 ? > >> >> > >> >> > md1 is a RAID 0 used to combine two 750GB drives I already had so that > >> >> > >> >> ...as used here? > >> >> > >> >> > Detecting md0. Can't start md0 because it's missing a component (md1) > >> >> > and thus wouldn't be in a clean state. > >> >> > Detecting md1. md1 started. > >> >> > Then I use mdadm to stop md0 and restart it (mdadm --assemble md0), > >> >> > which works fine at that point because md1 is up. > >> >> > >> >> Did you try changing your configurations uch that md0 is the RAID 0 > >> >> and md1 is the RAID 5 array? > >> >> > >> > > >> > Or just swap the order of the two lines in /etc/mdadm.conf. > >> > > >> > NeilBrown > >> > > >> > >> I thought about trying that, but I was under the impression that the > >> autodetect process didn't refer to that file at all. I take it I was > >> mistaken? If so that sounds like the simplest fix. > > > > Depends what you mean by the "auto detect" process. > > > > If you are referring to in-kernel auto-detect triggered by the 0xFD partition > > type, then just don't use that. You cannot control the order in which arrays > > are assembled. You could swap the name md1 and md0 (Which isn't too hard > > using --assemble --update=super-minor) but it probably wouldn't make any > > change to behaviour. > > I'm not using the 0xFD partition type - the partitions my RAIDs are > composed of are all 0xDA, as suggested in the linux raid wiki. (I'd > provide the link but the site seems to be down at the moment.) I > believe that type is suggested specifically to avoid triggering the > kernel auto-detect. Good. So mdadm must be doing the assembly. What are the conrents of /etc/mdadm.conf (or /etc/mdadm/mdadm.conf)? If you stop both arrays, then run mdadm --assemble --scan --verbose what is reported, and what happens? The kernel logs should give you some idea of what is happening at boot - look for "md" or "raid". NeilBrown > > I followed the directions on the wiki for creating the arrays, > creating the file system, etc (including keeping my /etc/mdadm.conf > updated) and nothing ever really called out what to do to get it all > mounted automatically at boot. I was going to worry about getting them > built now and getting them automated later, but when a bug (mentioned > in another thread) forced me to reboot I was surprised to see that > they were autodetected (more or less) anyway. So I'm not sure if it's > the kernel doing it or mdadm or what. I don't see any kind of entry > for mdadm when I run "rc-update show", so if it's mdadm doing the > detecting and not the kernel I have no idea what's kicking it off. > > Is there something I could look for in the logs that would indicate > how the RAIDs are actually getting assembled? > > > > > Get disable in-kernel autodetect and let mdadm assemble the arrays for you. > > It has a much better chance of getting it right. > > Assuming it's the kernel doing the assembling now, what are the > specific settings in the config I need to turn off? How would I get > mdadm to do the assembling? Just put the same commands I use when > doing it manually into a script run during the boot process? Or is > there already some kind of mechanism in place for this? > > > > > NeilBrown > > > > Sorry for all the questions. When the wiki addresses a topic it does a > good job, but if it's not mentioned it's pretty hard to find good info > on it anywhere. -- 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
