On Tuesday January 25, brad@xxxxxxxxxx wrote: > Been trying for days to get a software RAID 0+1 setup. This is on SuSe > 9.2 with kernel 2.6.8-24.11-smp x86_64. > > I am trying to setup a RAID 0+1 with 4 250gb SATA drives. I do the > following: > > mdadm --create /dev/md1 --level=0 --chunk=4 --raid-devices=2 /dev/sdb1 > /dev/sdc1 > mdadm --create /dev/md2 --level=0 --chunk=4 --raid-devices=2 /dev/sdd1 > /dev/sde1 > mdadm --create /dev/md0 --level=1 --chunk=4 --raid-devices=2 /dev/md1 > /dev/md2 > > This all works fine and I can mkreiserfs /dev/md0 and mount it. If I am > then to reboot /dev/md1 and /dev/md2 will show up in the /proc/mdstat > but not /dev/md0. So I create a /etc/mdadm.conf like so to see if this > will work: > > DEVICE partitions > DEVICE /dev/md* > ARRAY /dev/md2 level=raid0 num-devices=2 > UUID=5e6efe7d:6f5de80b:82ef7843:148cd518 > devices=/dev/sdd1,/dev/sde1 > ARRAY /dev/md1 level=raid0 num-devices=2 > UUID=e81e74f9:1cf84f87:7747c1c9:b3f08a81 > devices=/dev/sdb1,/dev/sdc1 > ARRAY /dev/md0 level=raid1 num-devices=2 devices=/dev/md2,/dev/md1 > > > Everything seems ok after boot. But again no /dev/md0 in /proc/mdstat. > But then if I do a mdadm --assemble --scan it will then load > /dev/md0. My guess is that you are (or SuSE is) relying on "autodetect" to assemble the arrays. Autodetect cannot assemble an array made of other arrays. Just an array made of partitions. If you disable the autodetect stuff and make sure mdadm --assemble --scan is in a boot-script somewhere, it should just work. Also, you don't really want the "device=/dev/sdd1..." entries in mdadm.conf. They tell mdadm to require the devices to have those names. If you add or remove scsi drives at all, the names can change. Just rely on the UUID. > > Also do I need to create partitions? Or can I setup the whole drives as > the array? You don't need partitions. > > I have since upgraded to mdadm 1.8 and setup a RAID10. However I need > something that is production worthy. Is a RAID10 something I could rely > on as well? Also under a RAID10 how do you tell it which drives you want > mirrored? raid10 is 2.6 only, but should be quite stable. You cannot tell it which drives to mirror because you shouldn't care. You just give it a bunch of identical drives and let it put the data where it wants. If you really want to care (and I cannot imagine why you would - all drives in a raid10 are likely to get similar load) then you have to build it "by hand" - a raid0 of multiple raid1s. 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
