Thoughts on BTRFS

[triggerhurt]

First of all thank you guys for all the work you put into xbian. I personally tried all rpi "OSes" which provide xbmc/kodi and xbian is by far the best one. Thank you for that! Much, much appreciated!

HOWEVER there is one particular thing which I really dislike, well that's not completely true... OK let's talk about BTRFS.

I like BTRFS. Some of my daily-work paritition run on BTRFS (on my pc (!)). But in the years I have a rpi (and i have now 4 PIs and of course I started with model A) xbians BTRFS was the main reason why I had to spend hours and hours fixing sth. that was broken because of BTRFS. I had various powerloss issues (because of actual powerloss, dont blame my various powersupplies) after which i was not able to boot again. One time i had serious issues with my SD-card being full. It wasn't full but btrfs wasnt freeing unused space. Resizing processes failed. The conversion-process utterly failed me, ... ,...

Xbian is most of the time so easy to use but a lot of btrfs-involved stuff is the total opposite.

Maybe I can make a long story short: I have around 7 years of raw-debian experience, I do programming since 15 years as a hobby (learned 6/10 C++ skills all by myself; can do mysql,php,python,java(=sucks) you name it, studying ~"commercial information technology" in germany) and something around 90% percent of the combined approx. 30-40 hours I spent fixing / reinstalling xbian were due to BTRFS! It wasn't my config. It wasn't your OS. It wasn't xbmc. It wasn't kodi.

And the thing is that I am sort of capable of detecting whats probably wrong and what has to be done but someone else will just say: "well xbian just sucks, it crashes all the time especially on powerloss which was not the case on XYZ which is far better".

Today I cut the power (which was not a good idea but I did it before without problems). RPI2 had nothing to do. On restart: Black Screen and login. /home/* was gone. I had to spent two hours of messing around with btrfs to recover that damn remote-config for kodi which I should have backed up but didn't but thats not the problem. From my point of view: It's BTRFS. BTRFS is just great but it is not on the PI. It just isn't! From my vast experience with all models of the pi except the model B (not +) I can say that. About half a year or so I decided to change/hack NOTHING on xbian because no matter how debian friendly or acceptable it is, it improves chances of me spending some surprise hours on some stupid bug. Well it still lets me down (exhibit A incident today) and I consider myself to be an experienced user.

I know you surely have one or two really big BTRFS fans in your dev-crew and I respect that. BTRFS has such potential, you can do a lot with it and I really do think xbian does a LOT with BTRFS BUT in my opinion the Raspberry Pi just don't seem to be a solid enough platform for BTRFS. IT JUST ISN'T! I know you spend a lot of work into BTRFS on xbian but please, PLEASE get back to something solid. Something that can take a punch on the rpi. Something like ext4 or so. Please! BTRFS solves Problems you would not have otherwise! BTRFS is probably the best filesystem around but the Pi and the fact that sometimes you just have to cut the power just don't seem capable of running it properly + a lot of good stuff is only used by the ultra-btrfs-geeks!

I beg you guys! Please spare me the future time of my life messing the same shitty behaviour over and over again! And please do see the other point: a normal user will probably never distinguish between xbian failure or a btrfs related failure. She/He will just be pissed to get the current image, prepare sd-card, ... He/She will probably come to the conclusion that "bleeding edge" is not worth 5 hours of bugfixing or 2 hrs of reinstall every 2-3 months, especially when He/She just wanted to watch a movie at the very moment BTRFS let them down

P L E A S E

[CurlyMo]

Before your first boot, have you tried setting rootfstype to ext4? I believe it should then just use ext4 as the filesystem.

[Fabio72]

@triggerhurt

I have the same issues you have with unclean shutdowns, but my system is running on nfs root

[triggerhurt]

(24th Apr, 2015 08:08 PM)CurlyMo Wrote:  Before your first boot, have you tried setting rootfstype to ext4? I believe it should then just use ext4 as the filesystem.

This sounds interesting! So I have to dd the sdcard and then I mount it and change that and xbians installer will create an ext4 fs?

[CurlyMo]

You install XBian, but before you first boot it, you change btrfs to ext4 in the cmdline.txt.

[triggerhurt]

Thank you very much! I will definitely try that

[Exnor]

(27th Apr, 2015 03:22 AM)CurlyMo Wrote:  You install XBian, but before you first boot it, you change btrfs to ext4 in the cmdline.txt.

Going to try that too... not that i had any problems with BTRFS but i just want to debug the latest Kodi low performance on my 2 rPi model 1 B.

[jiminlaw]

I had the same thoughts and problems about BTRFS on XBian. It's hard to explain to the girlfriend that the RaspberryPi is the greatest thing in the world when I have to constantly re-flash the image on the device.

So, I tried changing to rootfs=ext4 (before first boot) but it sent to the recovery boot console with the following error:

mount -t ext4 -o rw,subvol=root/@,thread_pool=2,autodefrag,compress=lz4,commit=120 /dev/mmcblk0p2 /rootfs
mount: wrong fs type, bad option, bad superblock on /dev/mmcblk0p2, missing codepage or helper program, or other error

I then tried to format the /dev/sdb2 partition into ext4 but I got the same error.
I'm thinking it has something to do with the compress=lz4 option/argument and I'll try removing that later on.
Just thought I'd let others know and if someone else has a better solution, please let me know.

[CurlyMo]

Please also remove all the options after rw

[jiminlaw]

(3rd Jun, 2015 07:37 AM)CurlyMo Wrote:  Please also remove all the options after rw

So, just to confirm, it should just be:
mount -t ext4 -o rw /dev/mmcblk0p2 /rootfs

Right?

[CurlyMo]

Yes, all the other options are specific for btrfs.

[tehdartherer]

If I change it to ext4, is it still possible to use the usb installer from xbian-config?
I was messing around with a superblock error on btrfs, but unfortunately there is no btrfs-select-super binary in your btrfs-tools package. So I maybe try ext4.

[CurlyMo]

I believe so.

[Exnor]

Any advantage on reverting/changing the FS to ext4?