BTRFS and lilo

jenkler · Posted: Sat Jan 28, 2012 1:15 pm Post subject: BTRFS and lilo

EDIT - GOOD TO KNOW:
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Enable CONFIG_BOOT_DELAY=y
Then append boot_delay=200 at lilo boot
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Hello everyone!

Just want to know is anyone has got it to work with lilo and btrfs

I want to boot af a 2 disk system in btrfs mirror mode from lilo native. No boot partition or initrd.

please share any findings ;-)

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Gusar · Posted: Sat Jan 28, 2012 2:07 pm Post subject:

I know it's a stupid question, but I have to ask anyway, and you for sure have predicted that it will be asked. So here we go: Why?

Follow-up question: Have you considered syslinux?

Ant P. · Veteran Joined: 18 Apr 2009 Posts: 1920 Location: UK

You have four options:

Use an initrd.
Use a separate /boot partition.
Use a Btrfs-compatible bootloader.
Fix LILO yourself.

What you're asking is not currently possible.

jenkler · Posted: Sun Jan 29, 2012 2:04 pm Post subject: yeah

I relly want lilo :-D

but i don't have the knowlage to patch it :-(

, in other wrods i need to wait
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Etal · Veteran Joined: 15 Jul 2005 Posts: 1633

jenkler · Posted: Fri Mar 16, 2012 8:17 am Post subject: Re: yeah

XavierMiller · Posted: Fri Mar 16, 2012 8:41 am Post subject:

Hello,

Syslinux (extlinux) is compatible with BTRFS, as I see in their websites. This could be an alternative to LILO.

(BTW I switched from GRUB to SYSLINUX because of GRUB2 mess)
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jenkler · Posted: Fri Mar 16, 2012 9:41 am Post subject: I now have an setup...

Raid 1:

mkfs.btrfs -m raid1 -d raid1 /dev/sda /dev/sdb

boot on usb stick (lilo in mbr) /dev/sdc

mkfs.ext4 /dev/sdc

i have /dev/sda and /dev/sdb in raid1 setup without any partitions, msdos or GPT tables, just plain discs

i boot from /dev/sdc with lilo and tried to append this but it does not work.

append = "root=/dev/sda rootfstype=btrfs rootflags=device=/dev/sda,device=/dev/sdb"

I get this: http://imagebin.org/203685

if i do this only

append = "root=/dev/sda" or use root = /dev/sda

I get this: http://imagebin.org/203687
it finds btrfs but is unable to setup the array
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kingfame_147 · Apprentice Joined: 11 Oct 2008 Posts: 167

Hi,

let's start with the second cmdline:

This is intend to happen :) You have a multi disk btrfs and don't do a "btrfs device scan". Therefore btrfs tries to mount a multi disk fs with only one known device with has to fail. append "rootflags=degraded" to your second cmdline and it will work. However, you will only use one device. In you case I would test this one time to see if your filesystem is ok.

First cmdline:

Unfortunately I never used lilo nor have any idea how to use it.

What I would do: Grab a live cd and play around a little bit. Do something like "mount -o degraded /dev/sda /mnt", then "mount -o device=/dev/sda,/dev/sdb /dev/sda /mnt" and see if it works. If this works there is something wrong the way you tell lilo to mount your root device. If this doesn't work there is something wrong with your filesystem.

jenkler · Posted: Fri Mar 16, 2012 11:03 am Post subject: Thanks

kingfame_147 · Apprentice Joined: 11 Oct 2008 Posts: 167

You don't need the subvol= part if you don't use subvolumes. btrfs creates a default subvolume which is mounted if no subvol= is used.

I actually don't know if the rootflags is broken, because I don't know how lilo handles those :( In image it looks like there is a = missing, like "rootflags device=/dev.." instead of "rootflags=/dev/...". But this could be because of the picture.

Syslinux isn't a bootloader, isn't it? It doesn't matter if you use grub or lilo, you just have to use the right syntax.

Live CD:

Ok, that's a good sign :) Your filesystem works. But don't use the degraded option as a workaround. It is only a test. Normally you use this option in a raid if one device is broken and you want to replace it.

The second test is failing because you have to umount the device first "umount /mnt/gentoo", then try the command again. If it works: There is something wrong with your lilo configuration. Somebody who know how to use lilo has to help you out then.

Btw: Why don't you just use dracut as an initramfs? It is very easy to setup and will really help you with btrfs.

Gusar · Posted: Fri Mar 16, 2012 12:17 pm Post subject:

jenkler · Posted: Fri Mar 16, 2012 12:19 pm Post subject:

mount -o degraded /dev/sda /mnt/gentoo
then
mount -o remount,rw,device=/dev/sda,device=/dev/sdb -t btrfs /dev/sda /mnt/gentoo

works and seams to be correct

mount prints:
/dev/sda on /mnt/gentoo type btrfs (rw,device=/dev/sda,device=/dev/sdb)

but a workaround would be the degraded stuff + a remount from fstab or something. I dont want any intird and i want to use lilo, thats why this case is so hard to break

lilo does not support btrfs so i have the usbstick workaround and it works. I hope that this degraded tuff is not the only solution for me ...

I hate initrd, grub, genkernel and modules, it so fucking blooted. Sorry

append="rootfstype=btrfs root=/dev/sda rootflags=device=/dev/sdb"
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Gusar · Posted: Fri Mar 16, 2012 12:24 pm Post subject:

jenkler, don't you think it'd be much simpler to just use another bootloader, instead of futzing around with usb sticks and such? You can't have that big of a loyalty to a bootloader. I'd get it if it was a userspace app that's exactly what you want. But bootloader? As much as I like syslinux, I immediately went to grub on my netbook. Because it simply works better on that crazy machine.

jenkler · Posted: Fri Mar 16, 2012 12:33 pm Post subject:

Gusar: I love lilo because its simple and does not put alot of crap in the system + it silly but i have a boot logo that i like in lilo ;-D

I hate to giveup if its a small chance its possible to do this. There is allways gurus out there that know how to do it
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jenkler · Posted: Fri Mar 16, 2012 2:52 pm Post subject: Question!

How do I create device files at boot time without an initrd , anyone?

Do i need to patch something ?
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Gusar · Posted: Fri Mar 16, 2012 3:02 pm Post subject:

There's devtmpfs. If you need anything beyond that, not possible without an initramfs.

jenkler · Posted: Fri Mar 16, 2012 3:31 pm Post subject:

AngelKnight · Tux's lil' helper Joined: 14 Jan 2003 Posts: 110

kingfame_147 · Apprentice Joined: 11 Oct 2008 Posts: 167

@AngelKnight

As I mentioned before btrfs doesn't need the btrfs device can. You can simply mount any multi device btrfs with via

AngelKnight · Tux's lil' helper Joined: 14 Jan 2003 Posts: 110

[quote="kingfame_147"]@AngelKnight

As I mentioned before btrfs doesn't need the btrfs device can. You can simply mount any multi device btrfs with via

kingfame_147 · Apprentice Joined: 11 Oct 2008 Posts: 167

?! A loss of one disk isnt a problem at all. Just add the "degraded" option to the rootflags, replace the disk with a new one and remove the "degraded" option.