On Dec 1 2007 06:19, Justin Piszcz wrote: > RAID1, 0.90.03 superblocks (in order to be compatible with LILO, if > you use 1.x superblocks with LILO you can't boot) Says who? (Don't use LILO ;-) >, and then: > > /dev/sda1+sdb1 <-> /dev/md0 <-> swap > /dev/sda2+sdb2 <-> /dev/md1 <-> /boot (ext3) > /dev/sda3+sdb3 <-> /dev/md2 <-> / (xfs) > > All works fine, no issues... > > Quick question though, I turned off the machine, disconnected /dev/sda > from the machine, boot from /dev/sdb, no problems, shows as degraded > RAID1. Turn the machine off. Re-attach the first drive. When I boot > my first partition either re-synced by itself or it was not degraded, > was is this? If md0 was not touched (written to) after you disconnected sda, it also should not be in a degraded state. > So two questions: > > 1) If it rebuilt by itself, how come it only rebuilt /dev/md0? So md1/md2 was NOT rebuilt? > 2) If it did not rebuild, is it because the kernel knows it does not > need to re-calculate parity etc for swap? Kernel does not know what's inside an md usually. And it should not try to be smart. > I had to: > > mdadm /dev/md1 -a /dev/sda2 > and > mdadm /dev/md2 -a /dev/sda3 > > To rebuild the /boot and /, which worked fine, I am just curious > though why it works like this, I figured it would be all or nothing. Devices are not automatically readded. Who knows, maybe you inserted a different disk into sda which you don't want to be overwritten. > More info: > > Not using ANY initramfs/initrd images, everything is compiled into 1 > kernel image (makes things MUCH simpler and the expected device layout > etc is always the same, unlike initrd/etc). > My expected device layout is also always the same, _with_ initrd. Why? Simply because mdadm.conf is copied to the initrd, and mdadm will use your defined order. - 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
