[Plan9]

I used the btrfs-convert tool on my ext4 volume and while the conversion was a success, now ArchLinux mounts root as read only. (I know the file system is fine as I can remount the file system once the OS has started)

I'm using syslinux, but I'm pretty sure it's not the boot menu that's the issue. I think it's a Linux config file I've missed somewhere; likely a really obvious and dumb mistake that I've over looked.

I believe the fstab is correct (and I have changed a few settings in there just in case). And I've added btrfs to mkinitcpio.

Anyone else have any suggestions?

 

[particleman72]

can you mount rw after boot?

# mount -o remount,rw /;

 

[gonX]

Post fstab (cat /etc/fstab) and post the last 100 lines of dmesg (dmesg | tail -n 100) after boot.

 

[CaptainBlame]

You used a file system conversion tool; you are braver than me

 

[Plan9]

Quote:

Originally Posted by particleman72

can you mount rw after boot?

# mount -o remount,rw /;

I did already say I could

Quote:

Originally Posted by gonX

Post fstab (cat /etc/fstab) and post the last 100 lines of dmesg (dmesg | tail -n 100) after boot.

The last 100 lines wouldn't be of much use as that's all just wifi and other such crap. There is this further up though:

Code:

$ dmesg | egrep -i "(btrfs|sda)"                                                                                                                
[    0.000000] Command line: root=/dev/sda1 ro initrd=../initramfs-linux.img BOOT_IMAGE=../vmlinuz-linux                                                                
[    0.000000] Kernel command line: root=/dev/sda1 ro initrd=../initramfs-linux.img BOOT_IMAGE=../vmlinuz-linux 
[    1.412671] sd 0:0:0:0: [sda] 125045424 512-byte logical blocks: (64.0 GB/59.6 GiB)
[    1.412745] sd 0:0:0:0: [sda] Write Protect is off
[    1.412749] sd 0:0:0:0: [sda] Mode Sense: 00 3a 00 00
[    1.412782] sd 0:0:0:0: [sda] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA
[    1.414982]  sda: sda1
[    1.415445] sd 0:0:0:0: [sda] Attached SCSI disk
[    1.487440] Btrfs loaded
[    1.488171] device fsid b9a11d9a-7db6-46c3-b2f4-9b651f3e108b devid 1 transid 395 /dev/sda1
[    1.806315] device fsid b9a11d9a-7db6-46c3-b2f4-9b651f3e108b devid 1 transid 395 /dev/sda1
[    2.245862] device fsid b9a11d9a-7db6-46c3-b2f4-9b651f3e108b devid 1 transid 395 /dev/sda1
[    2.460893] device fsid b9a11d9a-7db6-46c3-b2f4-9b651f3e108b devid 1 transid 395 /dev/sda1
[    2.461807] btrfs: disk space caching is enabled
[    2.463332] btrfs: mismatching generation and generation_v2 found in root item. This root was probably mounted with an older kernel. Resetting all new fields.
[    2.463794] btrfs: mismatching generation and generation_v2 found in root item. This root was probably mounted with an older kernel. Resetting all new fields.
[    2.480639] Btrfs detected SSD devices, enabling SSD mode
[    2.481025] btrfs: mismatching generation and generation_v2 found in root item. This root was probably mounted with an older kernel. Resetting all new fields.
[    5.786825] device fsid b9a11d9a-7db6-46c3-b2f4-9b651f3e108b devid 1 transid 397 /dev/sda1
[    5.787612] btrfs: disk space caching is enabled
[    5.809776] Btrfs detected SSD devices, enabling SSD mode
[    5.809797] btrfs: mismatching generation and generation_v2 found in root item. This root was probably mounted with an older kernel. Resetting all new fields.
[    6.465721] device fsid b9a11d9a-7db6-46c3-b2f4-9b651f3e108b devid 1 transid 397 /dev/sda1
[   25.171509] btrfs: disk space caching is enabled

Code:

#UUID=58a3c64f-ba75-4f44-bad2-a24b05331b6a      /               btrfs           defaults,compress,ssd,discard           0 0
UUID=/dev/sda1               /               btrfs           defaults,noatime,discard,ssd,compress   0 0

I've just noticed that I've garbled up the fstab (used a block device against UUID), so going to fix that and reboot

[edit]
yeah that fixed it. Dumb mistake. I can't believe I missed that yesterday. Still, I did suspect it was something stupid I'd overlooked.

Thanks for your help
Quote:

Originally Posted by CaptainBlame

You used a file system conversion tool; you are braver than me

I know what you mean. I'm hoping to convert my work desktop to Btrfs to take advantage of snapshotting, however I thought I'd better check the conversion tool at home (where it matters less) first. Plus I wanted to get the feel of just how mature Btrfs is before committing to it.

Honestly though, even just with these little tests (and I'm not in any way blaming the booting in read only on Btrfs), I'm largely unimpressed. It's pretty obvious from using it that it's designed to be a copy of ZFS, yet the CLI tools aren't near as clean and user friendly. I honestly do wish Oracle (or whoever's decision it was) just wrote new ZFS drivers for Linux instead of trying to reinvent a crappier version of ZFS.

 

[gonX]

Good to hear you fixed it. You don't need to use the 'defaults' option in the fstab if you are specifying something else.

 

[Plan9]

Quote:

Originally Posted by gonX

Good to hear you fixed it. You don't need to use the 'defaults' option in the fstab if you are specifying something else.

This is what I thought too, but every single article I found, when googling the problem, did put defaults + other options:
https://btrfs.wiki.kernel.org/index.php/SysadminGuide
https://wiki.archlinux.org/index.php/Installing_on_Btrfs_root#.2Fetc.2Ffstab
http://tincman.wordpress.com/2011/01/20/installing-arch-linux-onto-a-gpt-partitioned-btrfs-root-ssd-on-a-legacy-bios-system/

 

[Plan9]

Btrfs is an abomination.

Every single thing that ZFS got right, btrfs completely cocked up. There isn't even a simple was to roll back snapshots. Its just the worst.

 

[Rookie1337]

Quote:

Originally Posted by Plan9

Btrfs is an abomination.

Every single thing that ZFS got right, btrfs completely cocked up. There isn't even a simple was to roll back snapshots. Its just the worst.

Wait so snapshots don't work or what? I'm totally confused on Btrfs as when I first used it back in 2010 with MeeGo it was faster than it is now...it also seemed to have less features working. So what's the point in going to btrfs (IIRC isn't it supposed to be the ext4 replacement in the future?) because I'm trying it on one Linux install and it has atrocious slow boots now and shutdowns.

 

[Plan9]

Quote:

Originally Posted by Rookie1337

Wait so snapshots don't work or what? I'm totally confused on Btrfs as when I first used it back in 2010 with MeeGo it was faster than it is now...it also seemed to have less features working. So what's the point in going to btrfs (IIRC isn't it supposed to be the ext4 replacement in the future?) because I'm trying it on one Linux install and it has atrocious slow boots now and shutdowns.

It's snapshots fine. It doesn't have any in built rollback feature (or at least none that I can fine) so you're basically expected to rsync your data manually (as one guide suggests)

 

[jrl1357]

^ snapshoting works, and so do most features found in ZFS, but not nearly as user-friendly or as clean as they do in ZFS.

 

[Plan9]

Quote:

Originally Posted by jrl1357

^ snapshoting works, and so do most features found in ZFS, but not nearly as user-friendly or as clean as they do in ZFS.

how do you rollback a snapshot of root? I can't find a single sane method of doing so.

 

[jrl1357]

Never said it was clean, but if you back up your kernel and initramfs you can snap/roll like any other volume... Although theres a package moving in the AUR to fix that.

 

[Plan9]

Quote:

Originally Posted by jrl1357

Never said it was clean, but if you back up your kernel and initramfs you can snap/roll like any other volume... Although theres a package moving in the AUR to fix that.

It's the kernel i wanted to rollback.

Without wanting to start a flamewar, I think I've been falling out of love for Linux in the last few months - and this is just another nudge pushing me towards running FreeBSD. I'm definitely having a crisis of faith lately

 

[jrl1357]

Why do you care about the kernel? Just chroot if you have a problem. If your compiling your kernel you could just keep the source.

But I agree, the latest changes from systemd to whole mir thing is a big negitive to most GNU/Linux distros. I havn't had time to get my FreeBSD install fully up because of school work, but I plan to make it my main install. As a thought though, have you considered trying a GNU/kFreeBSD (I think there is one based on arch now, if unstable) ?

 

[Shrak]

Quote:

Originally Posted by Plan9

It's the kernel i wanted to rollback.

Without wanting to start a flamewar, I think I've been falling out of love for Linux in the last few months - and this is just another nudge pushing me towards running FreeBSD. I'm definitely having a crisis of faith lately

Don't worry about that crisis, I've been mostly using OpenBSD lately because of some of the way things have been going in Linux generally and in Arch ( the general **** attitude by the dev team and forum, about some of the packages being forced onto us ).

 

[Plan9]

Quote:

Originally Posted by jrl1357

Why do you care about the kernel? Just chroot if you have a problem. If your compiling your kernel you could just keep the source.

because the nvidia drivers and what not are tied into the kernel and ABI versions
Quote:

Originally Posted by jrl1357

But I agree, the latest changes from systemd to whole mir thing is a big negitive to most GNU/Linux distros. I havn't had time to get my FreeBSD install fully up because of school work, but I plan to make it my main install. As a thought though, have you considered trying a GNU/kFreeBSD (I think there is one based on arch now, if unstable) ?

I like debian, but i couldnt run that as my desktop and ArchBSD (the Arch / FreeBSD hybrid you mentioned) isn't really mature enough to be used for anything serious.

 

[Plan9]

Quote:

Originally Posted by Shrak

Don't worry about that crisis, I've been mostly using OpenBSD lately because of some of the way things have been going in Linux generally and in Arch ( the general **** attitude by the dev team and forum, about some of the packages being forced onto us ).

I hear you on that.

 

[Rookie1337]

Quote:

Originally Posted by Plan9

I hear you on that.

Kind of OT but why must you guys leave.

If there aren't the admin orientated users like you around all there's going to be is the general user with a very limited understanding of Linux (AKA me) and we'll end up with a dumb terminal OS like droid.

 

[bomfunk]

Quote:

I like debian, but i couldnt run that as my desktop

Out of curiosity, why?