Arch Linux

genti

Member

Registered: 2017-02-07

Posts: 4

FakeRaid - Linux (Arch) vs Windows RAID boot assembly

This is not a proper issue since my computer works fine but I wanted to mention something and maybe get some pointers on how to troubleshoot further.

I have RAID0 for my dual boot partition (Arch and Windows). The least stable setup but I did it to pool the space from two 180GB SSDs and get some speed benefits. Home is a different device and everything is backed up.

My motherboard has an "Ultra Fast" boot option that basically is core UEFI without extras and it is indeed fast. I have setup rEFInd as the boot manager and that shows up fine under all combinations. Windows also boots fine under all combinations, even when called from within rEFInd. But under "Ultra Fast" Arch hangs and the issue seems to be that raid0 is not assembled during boot.

I have tried to add extra hooks and modules to /etc/mkinitcpio.conf with no luck. Normally I would have given up but how come Windows is able to assemble the raid no problem but the kernel fails?

This is the first time I am posting here and I want to thank the Arch developers for building a great OS with top-notch documentation.

Last edited by genti (2017-02-07 03:31:10)

Lone_Wolf

Member

From: Netherlands, Europe

Registered: 2005-10-04

Posts: 11,920

Re: FakeRaid - Linux (Arch) vs Windows RAID boot assembly

Is this a motherboard with an intel processor / chipset ?

Intel onboard raid often relies on the windows driver created by intel for advanced options like this one.

---

Disliking systemd intensely, but not satisfied with alternatives so focusing on taming systemd.

(A works at time B)  && (time C > time B ) ≠  (A works at time C)

genti

Member

Registered: 2017-02-07

Posts: 4

Re: FakeRaid - Linux (Arch) vs Windows RAID boot assembly

Yes, it is. My guess is that the BIOS skips the initialization and Windows does it. It might be possible for mdadm to do the same with a parameter but I don't know how. I moved the efi partition outside the RAID array to experiment in the future.
If anyone is interested here are relevant details

~
#cat /proc/mdstat
Personalities : [raid0]
md126 : active raid0 sda[1] sdb[0]
      351646720 blocks super external:/md127/0 128k chunks
     
md127 : inactive sdb[1](S) sda[0](S)
      4904 blocks super external:imsm

# cat /etc/mdadm.conf
DEVICE partitions
#
#ARRAY /dev/md/imsm0 metadata=imsm UUID=0c260d12:22989a34:431de946:4ff1b7b4
#ARRAY /dev/md/vol0_0 container=/dev/md/imsm0 member=0 UUID=9a695da3:9fe4fe9f:6ff56638:9f50181f

# from /etc/mkinitcpio.conf
MODULES="raid0 ext4"
BINARIES="mdmon mdassemble mdadm"
HOOKS="base udev autodetect modconf block mdadm_udev filesystems keyboard fsck"

# uname -a
Linux -- 4.9.7-1-ARCH #1 SMP PREEMPT Wed Feb 1 19:33:40 CET 2017 x86_64 GNU/Linux

00:1f.2 RAID bus controller: Intel Corporation SATA Controller [RAID mode] (rev 04)

When I enable the Ultra Fast mode on the bios and I get the emergency shell due to boot failure
# mdadm --detail-platform
mdadm: imsm capabilities not found for controller: /sys/devices/pci:0000:00/0000:00:1f.2 (type SATA)

Last edited by genti (2017-02-09 16:16:57)