Btrfs File-System Updates For Linux 4.6

[starshipeleven]

slight OT but btrfs mailing list refuses to receive my mails (must be in a blacklist or something).

I'm trying to run btrfs on a Marvell Kirkwood device (a pretty average and cheap home nas, 2 Sata ports, 512MB RAM, gigabit eth, ARM singlecore powerful enough to nearly saturate the gigabit port, some USB 2.0 and one usb 3.0) currently running Debian Jessie, it has a XOR engine that can hardware-accelerate the crc32c checksum (the checksum used in btrfs).
There are drivers for the XOR in linux, I see the mails in mailing lists about the driver being added and patched.

How do I check if this engine is used or not for btrfs?

[twicejr]

Of course, if you want the newest btrfs-tools (4.5.1 at the moment), there's a way without updating to this kernel already, just compile it and it will install to userspace.

#!/bin/bash
sudo apt-get install git asciidoc xmlto --no-install-recommends -y
#build-deps.
sudo apt-get install uuid-dev libattr1-dev zlib1g-dev libacl1-dev e2fslibs-dev libblkid-dev liblzo2-dev -y
cd /tmp
git clone git://git.kernel.org/pub/scm/linux/kernel/git/kdave/btrfs-progs.git
cd /tmp/btrfs-progs
./autogen.sh
./configure
make -j`grep -c ^processor /proc/cpuinfo`
sudo make install -j`grep -c ^processor /proc/cpuinfo`
rm /tmp/btrfs-progs -rf
cd ../ && bash


####[email protected]:/tmp$ btrfs --version
####btrfs-progs v4.5.1

[SystemCrasher]

but zfs is not mature on linux, there are just many clueless people

Furthermore,
1) Using CDDL-licensed ZFS with GPL-licensed kernel could be a violation of licensing, which is a big deal for corporate users who aren't exactly fond of idea of being caught on something like THIS. Sun had their wish to be incompatible with Linux. Let's respect it and see where is Sun and where is Linux, he-he. To the hell with CDDL.
2) Its third-party module. GPU drivers vs ubuntu have already shown us how this performs. You upgrade OS version. Boom, black screen. Despite of DKMS gpu driver could fail to build or start anyway. Bummer. Even more fun if same thing happens to rootfs driver, ha-ha. That's how one fucks their system up for the real.
3) Ubuntu default setup provides quite reasonable subvolumes setup by default. So one can snapshot /home and rest of system in independent manner. I wonder if zfs on ubuntu can do similar tricks.
4) Btrfs is integrated with Linux, chattr +C or cp --reflink are working, etc and it even reuses RAID algos from appropriate kernel modules (just heavily optimized math though, not block-level approaches/lvm/etc).

Speaking for myself, I'm dealing with VMs and SD card images and ability to cp --reflink them for cheap multi-version-alike approach is valuable ally to me. Now I can get "independent", "deduplcated" copy of VM or drive image in a blink of eye, while these are still "independent" files, by virtue of CoW. Not to mention it is handy keep some few snapshots in case something has gone terribly wrong, like infamous "rm -rf /usr /whatever/it/was", as seen in bumblebee epic bug.

[pal666]

all the people saying "zfs is mature, btrfs is not"

but zfs is not mature on linux, there are just many clueless people

[starshipeleven]

not much, since ubuntu added btrfs support long ago

Yeah, but y'know, all the people saying "zfs is mature, btrfs is not" are salivating at that and you cannot deny this. There are quite a bit here and in other forums. While btrfs is still undeniably very meh.

btrfs will of course win in the long run, but zfs is going to see some more use in the short term.

[pal666]

And it will increase quite a bit when Ubuntu adds zfs support.

not much, since ubuntu added btrfs support long ago

[dweigert]

I'm curious, what is the advantage of using BTRFS over EXT4 or XFS on the root filesystem? Or is it just because BTRFS is default for SLES?

When you have to patch multiple thousands of servers every quarter, being able to roll them back if something goes wrong is a huge benefit. Sometimes rebuilding and restoring from backups is not a productive use of time....

[starshipeleven]

btrfs has modern superior desing, zfs has obsolete design
zfs for linux is separate product with zero userbase, which implies zero stability. btrfs for linux is used by default by some enterprise distros with support(not all features) and by facebook

Add Netgear NASes to the btrfs list. They use btrfs.

also, zfs does have some userbase on linux, probably less than btrfs tho. And it will increase quite a bit when Ubuntu adds zfs support.

God I'll laugh when people's data will burn randomly when they used zfs on a non-ecc system. The more people use it, the more likely it becomes that someone will come crying about his data loss.

[Turtleggjp]

rollbacks

This. I'm using BTRFS as my root filesystem now on several systems running Gentoo Linux. Before doing software updates, I make a snapshot of the subvolume used for my root filesystem, which I can then boot to from grub instead of my main subvolume if something goes wrong (subvol=backup instead of subvol=root on kernel command line). I can then keep around as many of these "backup" subvolumes as I have room for to rollback to any point in time if I want. I also use different subvolumes to try out different desktop environments (subvol=kde4, subvol=plasma, subvol=gnome, etc.) without them "cross contaminating" each other. It's like having as many different OS installations as you want all contained within one file system.

[pal666]

How does Btrfs compare against ZFS nowadays?

btrfs has modern superior desing, zfs has obsolete design
zfs for linux is separate product with zero userbase, which implies zero stability. btrfs for linux is used by default by some enterprise distros with support(not all features) and by facebook