Messages in this thread | | | Date | Sat, 13 Apr 2002 16:55:38 -0700 | From | Mike Fedyk <> | Subject | Re: RAID superblock confusion |
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On Sat, Apr 13, 2002 at 01:29:05PM -0600, Richard Gooch wrote: > Luigi Genoni writes: > > > > > > > > > > > > Ehh, I ran into this a while ago. When you compile raid as modules > > > > > it doesn't use the raid superblocks for anything except for > > > > > verification. I took a quick glance at the source and the > > > > > auto-detect code is ifdefed out if you compiled as a module. > > > > > > > > Exactly where is this? A scan with find and grep don't reveal this. > > > > > > > > > > drivers/md/md.c > > > > > > in the ifndef MODULE sectioin. > > > > > > > > Ever since I have had raid compiled into my kernels. > > > > > > > > This is my relevant .config: > > > > CONFIG_MD=y > > > > CONFIG_BLK_DEV_MD=y > > > > CONFIG_MD_LINEAR=m > > > > CONFIG_MD_RAID0=m > > > > CONFIG_MD_RAID1=m > > > > CONFIG_MD_RAID5=m > > > > CONFIG_MD_MULTIPATH=m > > > > > > > > > > Set this to =y and you're set. > > > > > > I'd like to see this working from modules though. > > > > NO, please. There are hundreds of scenarios where that could be > > dangerous. Suppose you load the RAID module when all partitions are > > mounted, and two partiton in mirror are mount on different mount > > point (you can do this, raid module is not loaded, and so...). And > > now you load the module and md device is registered. That would not > > be really nice, also if it is ulikely that you could damnage your > > system > > The RAID code checks to see if there are busy inodes for each device > in a RAID set. So your hundreds of scenarios are not a problem. >
I had a machine that had raid1 setup correctly but was accidentally configured to root=/dev/hda1 (one member of the md0 raid1 set).
All was well until I noticed I wasn't rooting from md0, so reboot with new root=/dev/md0 and now my filesystem is b0rked (maybe because hdc1 was the primary mirror?).
Luckily I was still setting up that machine so I just reinstalled it.
This was with raid compiled into the kernel, so it's not a module checking issue, and I consider it a user error. But maybe someone else thinks different...
Just reporting in case someone is intereted...
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