Dimitri, LVM is great, one thing to watch out for: it is very slow compared to pure md. That will only matter in practice if you want to exceed 1GB/s of sequential I/O bandwidth. - Luke On 6/1/07 11:51 AM, "Dimitri" <dimitrik.fr@xxxxxxxxx> wrote: > Craig, > > to make things working properly here you need to create a config file > keeping both raid1 and raid0 information (/etc/mdadm/mdadm.conf). > However if your root filesystem is corrupted, or you loose this file, > or move disks somewhere else - you are back to the same initial issue > :)) > > So, the solution I've found 100% working in any case is: use mdadm to > create raid1 devices (as you do already) and then use LVM to create > raid0 volume on it - LVM writes its own labels on every MD devices and > will find its volumes peaces automatically! Tested for crash several > times and was surprised by its robustness :)) > > Rgds, > -Dimitri > > On 6/1/07, Craig James <craig_james@xxxxxxxxxxxxxx> wrote: >> Apologies for a somewhat off-topic question, but... >> >> The Linux kernel doesn't properly detect my software RAID1+0 when I boot up. >> It detects the two RAID1 arrays, the partitions of which are marked >> properly. But it can't find the RAID0 on top of that, because there's no >> corresponding device to auto-detect. The result is that it creates /dev/md0 >> and /dev/md1 and assembles the RAID1 devices on bootup, but /dev/md2 isn't >> created, so the RAID0 can't be assembled at boot time. >> >> Here's what it looks like: >> >> $ cat /proc/mdstat >> Personalities : [raid0] [raid1] >> md2 : active raid0 md0[0] md1[1] >> 234436224 blocks 64k chunks >> >> md1 : active raid1 sde1[1] sdc1[2] >> 117218176 blocks [2/2] [UU] >> >> md0 : active raid1 sdd1[1] sdb1[0] >> 117218176 blocks [2/2] [UU] >> >> $ uname -r >> 2.6.12-1.1381_FC3 >> >> After a reboot, I always have to do this: >> >> mknod /dev/md2 b 9 2 >> mdadm --assemble /dev/md2 /dev/md0 /dev/md1 >> mount /dev/md2 >> >> What am I missing here? >> >> Thanks, >> Craig >> >> ---------------------------(end of broadcast)--------------------------- >> TIP 1: if posting/reading through Usenet, please send an appropriate >> subscribe-nomail command to majordomo@xxxxxxxxxxxxxx so that your >> message can get through to the mailing list cleanly >> > > ---------------------------(end of broadcast)--------------------------- > TIP 3: Have you checked our extensive FAQ? > > http://www.postgresql.org/docs/faq >
