mdadm_udev fails to assemble incomplete arrays sometimes

kvanberendonck · 2012-09-20 10:24:34

I tried making a RAID1 array as follows:

/dev/sda2 -W --write-behind
/dev/ram0 -b internal

The theory was to sync the drive to the ram each time I boot up and use it was a huge buffer. This was working perfectly! Doubled my battery life! And it did for a few reboots until I swapped to systemd and then everything went haywire-ish and race-y, which is a real shame because I can't stand an installation without systemd.

What would occasionally happen is that using the mdadm_udev hook the array wouldn't start itself at boot, at all. I'd get "root device not found: UUID=blahblah" and have to manually run mdadm --assemble on the device and type "exit" twice to get out of the grub recovery shell. Other times it did find the device, but wouldn't start it because members were missing and I'd have to manually mdadm /dev/mdX --run then mount it.

Is there any modifications I can make to mkinitcpio scripts to better do what I want OR is there a way I can have the brd ramdisk loaded and starting to sync before the initramfs image has finished.

I've already tried using rootwait and rootdelay=20 but they don't seem to change the fact that mdadm sometimes fails to autoassemble or start the devices completely.

Last edited by kvanberendonck (2012-09-20 10:50:14)

falconindy · 2012-09-20 12:40:43

kvanberendonck wrote:

until I swapped to systemd and then everything went haywire-ish and race-y, which is a real shame because I can't stand an installation without systemd.

systemd isn't even running at this point in the boot process.

mdadm_udev relies entirely on an upstream provided udev rule for array assembly. If it isn't working, I suggest bringing up your concerns upstream.

kvanberendonck · 2012-09-20 14:06:25

I doubt upstream will worry too much about the abusive way I'm using RAID :\ I'm sure it's my fault that it isn't working.

Arch Linux

#1 2012-09-20 10:24:34

mdadm_udev fails to assemble incomplete arrays sometimes

#2 2012-09-20 12:40:43

Re: mdadm_udev fails to assemble incomplete arrays sometimes

#3 2012-09-20 14:06:25

Re: mdadm_udev fails to assemble incomplete arrays sometimes

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