Hi,
I don't think this is likely to be a Gentoo issue but I figured I'd
ask here first before going elsewhere. (LKML, linux-raid, elsewhere)
Additionally it's not a critical problem at all but rather something
I'd like to try and understand and then report if appropriate.
On my main i7-980x machine I've been wanting to move root away from
an old 3-disk 50GB RAID1 that I built first built the machine with to
a newer 150GB RAID6. Toward this end the machine has two complete
Gentoo builds on it:
c2stable ~ # cat /proc/mdstat
<SNIP>
md3 : active raid6 sdc3[1] sdd3[2] sdb3[0] sde3[3] sdf3[5]
157305168 blocks super 1.2 level 6, 16k chunk, algorithm 2 [5/5] [UUUUU]
md126 : active raid1 sdd5[2] sdc5[1] sdb5[0]
52436032 blocks [3/3] [UUU]
unused devices: <none>
c2stable ~ #
md126 is the older RAID1, md3 is the newer RAID6. The are both built
on parts of the 5 hard drives in the box.
The two builds are intended to be identical. Same packages installed,
same kernel with the only exception being the RAID6 uses an initramfs
built into it. A diff of the two kernel configs shows only that
difference:
c2stable ~ # diff /usr/src/linux/.config /mnt/newRAID6/usr/src/linux/.config
137c137,139
< CONFIG_INITRAMFS_SOURCE=""
---
> CONFIG_INITRAMFS_SOURCE="/usr/src/initramfs.config"
> CONFIG_INITRAMFS_ROOT_UID=0
> CONFIG_INITRAMFS_ROOT_GID=0
142a145,146
> CONFIG_INITRAMFS_COMPRESSION_NONE=y
> # CONFIG_INITRAMFS_COMPRESSION_GZIP is not set
c2stable ~ #
In my grub.conf file I have three methods of booting the machine.
There are two methods of booting the RAID1 config, using the device
name and using the label. For the RAID6 I have only the label method:
(NOTE: Snipped out backup kernels just to clarify)
c2stable ~ # cat /boot/grub/grub.conf
default 0
timeout 15
splashimage=(hd0,0)/boot/grub/splash.xpm.gz
title RAID1 3.6.11-gentoo
root (hd0,0)
kernel (hd0,0)/boot/bzImage-3.6.11-gentoo root=/dev/md126
title RAID1 3.6.11-gentoo using LABEL
root (hd0,0)
kernel (hd0,0)/boot/bzImage-3.6.11-gentoo root=LABEL=RAID1root
title RAID6 3.6.11-gentoo using LABEL
root (hd0,0)
kernel (hd0,0)/boot/bzImage-RAID6-3.6.11-gentoo root=LABEL=RAID6root
c2stable ~ #
c2stable ~ # e2label /dev/md126
RAID1root
c2stable ~ # e2label /dev/md3
RAID6root
c2stable ~ #
The results are:
1) RAID1 using md126 boots fine
2) RAID1 using label of RAID1root fails
3) RAID6 using label of RAID6root boots fine
The failure is a kernel crash before the machine gets very far so
the only capture I might be able to try is with a camera and then post
that on line, but the screen is 80x25 and it's just a kernel crash so
there's very little data on the screen when the machine dies.
I've been Googling around for a couple of days but haven't found
anything very interesting. I figured I'd ask here first just to see
what ideas come up.
Thanks,
Mark
