odd problem with raid array
Still struggling to get this new box set up the way I'd like it:
- had to install a new kernel to see high memory (thanks!)
- took a while to figure out that a string of "devfs_mk_dev: could not
append to parent for /disc" errors are not dangerous (apparantly they show
up when putting root on LVM on RAID) - and that devfs is about to go away
in newer kernels
- now wrestling with on remaining problem, and I'd appreciate any help
anybody can offer:
I have four disks, several partictions each, with several raid-1
(software) volumes defined on top of these, used as follows:
/boot (raid 1)
/ (LVM on raid 1)
/backup (LVM on raid 1)
swap (raid 1)
Each of these is built with two active devices and one spare device.
Here's what's funny:
- all of these set up properly EXCEPT root. Root comes up with its two
active devices, but doesn't seem to even try to bind the spare device (no
entry in the kernel log)
/etc/mdadm/mdadm.conf seems to be set up correctly (it was set up
initially by the installer):
server1:/var/log# more /etc/mdadm/mdadm.conf
ARRAY /dev/md3 level=raid1 num-devices=2 spares=1
ARRAY /dev/md2 level=raid1 num-devices=2 spares=1
ARRAY /dev/md1 level=raid1 num-devices=2 spares=1
ARRAY /dev/md0 level=raid1 num-devices=2 spares=1
here's the relevant entry from the console display
###here's where /dev/md1 - my swap device is started
md: md1 stopped.
raid1: raid set md1 active with 2 out of 2 mirrors
mdadm: /dev/md1 has been started with 2 drives and 1 spare.
###and right afterwards is where /dev/md2, my root fs is strated
raid1: raid set md2 active with 2 out of 2 mirrors
mdadm: /dev/md2 has been started with 2 drives.
in this case, it doesn't seem to even try to bind /dev/sdb3 - no error
messages about it not being fresh, or anything - it just doesn't seem to
note: after everything comes up, if I try:
mdadm /dev/md2 -a /dev/sdb3
it works just fine (as confirmed with mdadm --detail)
As a work-around, I guess I could mount it in a local init file, after
everything else comes up, but that seems like a kludge. I'd rather
understand what's going on. About the only thing I can think of is that
something is going on early in the boot cycle, since there's a
"root=/dev/mapper/rootvolume-rootlv" in my kernal boot config, that
eventually maps onto /dev/md2.
Any thoughts, debug suggestions.
Thanks very much - I think this is the last nit I have to pin down before
starting to put real apps on this box.