Missing RAID support for Alpha ?

LasseKongo · n00b Joined: 01 Aug 2003 Posts: 17 Location: Sweden

I just acquired an Alpha machine (Personal Workstation 500) which I intend to run Linux on.
I have equipped the machine with 2 18GB drivers which I intend to mirror with software RAID
and also boot from the mirror.
When I booted the Gentoo 2007.0 installcd I found that there are no RAID or LVM modules
whatsoever, and the are not statically compiled into the kernel either (but mdadm exists).
After reading posts on Google, a lot of people seem to think that it is not possible to boot
from a mirror, at least not with SRM/aboot.
I then downloaded Debian 4.0 which had all the necessary modules and mdadm included, and
after some quirks I got the mirror up and installed the base system with debbootstrap and then
successfully booted the system from the mirror.

So my question is, why is there no RAID support in the installcd kernel ? Are there known problems
when including them ?

Is there some way I can build my own kernel/installcd to get around this ?

/Daniel

neysx · Retired Dev Joined: 27 Jan 2003 Posts: 795

It was simply forgotten. 2007.1 should allow you to set up your system like you did.
Anyway, as you already know, Gentoo media is not required at all.
Any media that gives you access to your disks and Internet is all you need.

Hth

LasseKongo · n00b Joined: 01 Aug 2003 Posts: 17 Location: Sweden

Thanks for that info.

The potential problem I see is even if the modules are included and loaded at boot
it will not detect the arrays since there is no FD partition ID available when using
BSD disklabels. I my Debian experiment I used ext2 partition IDs and then Debian
embeds mdadm and an /etc/mdadm.conf with info on the root array
into the initramfs that loads when booting the kernel.
How does Gentoo handle such features in initrd/initramfs? When I checked on my PC
with Opensuse 10.3 there is a ton of features that can be embedded into the initrd of
that OS.
I don´t have a machine at the moment to check for myself, so if anyone could shed
some light on this it would be appreciated.

/Daniel

Lupin_the_3rd · Apprentice Joined: 03 Apr 2005 Posts: 168

Yes, I'm running Gentoo on an XP1000 and I found it rather irritating that RAID1 module was not available on the install CD.

Anyhow, I am finally up and running on software RAID. SRM / aboot cannot boot from a Linux software RAID device though, so I came up with a creative solution to that problem! :wink:

I took an old 128 MB ConpactFlash card I had here, and bought a $10 CF-to-IDE adapter, then attached that to an IDE-SCSI adapter. So now I have this 128 MB scsi "drive" on the onboard Qlogic controller that SRM can boot from! Hooray! I don't use initrd; I have RAID support compiled into the kernel, so once the kernel boots, it identifies my software RAID1 mirror and system is running! Actually works very well. The CF card is mounted as /boot on my system.

The CF card has BSD disk label so that SRM / aboot can see it and boot the kernel, then my two SCSI disks (36 GB 10k rpm) both have DOS disklabels to allow the correct type "FD" "Linux RAID Autodetect" partition type.