Some observations in raid0 (successful boot in raid0 linux3 kernel)

Question

Have prepared a two -drive raid0 bootable Compact Flash system.
When first assembled it was in Kernel26v39 and booted into operating system and performed well. 
I have upgraded a pair of CF cards to linux 3.1.5-1 and they no longer can boot into an operating system.
The boot sequence performs :
decompressing linux ...parsingELF....done
Booting the kernel...
starting udevd
running HOOK [udevd]
Triggering uevents....done
Running HOOK [mdadm]
Waiting 10 seconds for /dev/disk/byuuid...................................................
ERROR: unable to determine major-minor..............................................
ramfs/#
So the root device, which is /dev/md0, is not recognized.
I have performed ls dev at the ramfs prompt and /dev/md0 is not listed.
I have performed blkid at the ramfs prompt and the /dev/md0 UUID is not listed.
However, I can boot into HDD linux3.1.5-1 and find /dev/md0 in ls dev and also find /dev/md0 listed in blkid.
Perhaps the Linux kernel is missing a parameter which enables mdadm via /etc/mdadm.conf or mdadm does not correctly generate the uuid for /dev/md0.
Since the device /dev/md0 is actually present in linux3.1.5-1 when booted in HDD, it is obviously valid.
The grub in use for the failed boot is grub1.99.  Partitioned boot is utilized and may be part of the problem although it seems not since the system begins loading after the grub prompt of ARCH LINUX...ARCH LINUX_FALLBACK.
Therefore the difficulty is inherent in the kernel/udev/mdadm interface.
I enjoy very much the raid0 bootable system performance with CF cards and would like to stay up to latest kernel if that be possible.
Modern arch linux can do anything?
The initramfs items have been included in the grub area.  Perhaps other items need attention as well?
Last edited by lilsirecho (2012-01-04 07:52:57)

Answer 1

Attempting to find a solution, I proceeded to modify grub at the prompt.
Changed :
set root = (hd0,1)....changed to (hd1,1)
linux ....added ....root=/dev/md0
The system booted into linux3.1.6-1 xfce4 Desktop.
Success!
EDIT:  hdparm results.......
sh-4.2# hdparm -t /dev/md0
/dev/md0:
Timing buffered disk reads: 534 MB in 3.01 seconds = 177.61 MB/sec
sh-4.2# hdparm -t /dev/md0
/dev/md0:
Timing buffered disk reads: 542 MB in 3.00 seconds = 180.46 MB/sec
sh-4.2# hdparm -t /dev/md0
/dev/md0:
Timing buffered disk reads: 540 MB in 3.01 seconds = 179.46 MB/sec
sh-4.2#
System is x86_64 and boots to xfce4 Desktop in nine seconds.......
CF cards are maxell 400x 16GB and /dev/md0 is 29GB , root ext3 fs.
Last edited by lilsirecho (2012-01-04 09:40:14)