[Gllug] initrd images & building 2.6.x kernels

[Mike Brodbelt]

Nix wrote:
> On Mon, 12 Sep 2005, Mike Brodbelt mused:

> Ooo. Nice. Last I looked at it it needed userspace help to boot, but
> obviously this is no longer true (I guess that's what `RAID autostart'
> is, but I can't immediately see such an option in the Linux kernel
> config; perhaps I'm looking in the wrong place).

There used to be one, IIRR. Nowadays, I think partitions with the type
set to 0xfd are scanned and started at boot if MD support is compiled
statically into the kernel. I don't think anything else is needed.

This didn't used to play well with LVM, but I tink the current LWM
implementation works. When I looked at it last (some time ago) you could
have autostart RAID or LVM, but not both, and I chose to use AUTOSTART
RAID. LVM then consists of failing a disk out, re-partitioning it, and
resyncing. Rinse and repeat, and when you're done you can run xfs_growfs
to expand the filesystems (assuming you use XFS).

>>LILO and GRUB will both happily boot a kernel from a RAID1 these days as
>>well.
>
> But not a RAID5? Damn. :/

Sadly not... Though I have a 4 disk array in one machine, and /boot is a
two disk mirror, with the GRUB stage1 loader installed in the bootsector
of both disks. In theory if the primary disk fails, the new primary BIOS
disk should have a GRUB bootsector that'll load it up anyway. I confess
to not having tested this yet....

Mike.

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