Re: Mount multiple-device-filesystem by UUID

Duncan
2013-07-28T08:37:13Z

Duncan posted on Sat, 27 Jul 2013 22:14:02 +0000 as excerpted:

> btrfs raid1 root here, was initr*less until I switched to btrfs which is
> broken with direct-kernel-root-mount rootflags=device=whatever syntax.
>
> UUIDs are indeed userspace -- udev/systemd.  However, if your initr*
> includes udev, at least here, it "just works".
>
> I use root=LABEL=whatever here on the kernel commandline for root, and
> LABEL=whatever for non-root in fstab, but as long as udev has the
> directory in /dev/disk/*, mount should work with it, so
> root=UUID=whatever at the kernel commandline should work, as should
> UUID=whatever in fstab as the first field.

I can add...

* I use dracut as my initramfs generator, but with some of the default
modules stripped in ordered to create a leaner initramfs.

* It has a(n optional but obviously activated here) btrfs module that
among other things, runs btrfs device scan before attempting to mount
real-root.  That''s the critical bit that should be in your initramfs
before attempting to mount a multi-device btrfs.  With the btrfs
executable and a call to btrfs device scan, mount, and udev creating the
/dev/disk/by-*/ subdirs, an initramfs environment should really handle
pretty much all the mount options available to you at a full-booted
commandline.

--
Duncan - List replies preferred.   No HTML msgs.
"Every nonfree program has a lord, a master --
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