Btrfs root install: Is snappy compression available in Arch?

*nixer · 2012-03-23 13:18:09

Hi.

I'm reinstalling Arch after finally receiving a replacement hard-drive. I'm considering holding off creating a Btrfs for / until the "snappy" compression algorithm becomes available. Can anyone tell me if it's possible to do now?

My last install used a lzo compressed btrfs root.

hadrons123 · 2012-03-23 19:24:39

The official package is Not yet updated with that. It needs kernel support too.
http://www.phoronix.com/scan.php?page=n … px=MTA0MjQ

DSpider · 2012-03-23 19:56:41

They should focus on implementing an fsck and a recovery tool first. That's the biggest drawback from using btrfs right now, not disk compression. One power outage and you'll have to reinstall Arch!

graysky · 2012-03-23 20:54:33

@DS - I thought that the fsck support was merged in mainline 3.3? Looks like [core]/btrfs-progs are dated "0.19.20120110-2" and there is nothing in [testing] that is newer.

hadrons123 · 2012-03-24 01:15:13

Oracle declared btrfs to be stable few days ago.

http://groups.google.com/group/snappy-c … 7234c161cd --> look at the snappy release date.

Arch package says its unstable and it is the current version.

fowler · 2012-03-24 23:14:58

DSpider wrote:

They should focus on implementing an fsck and a recovery tool first. That's the biggest drawback from using btrfs right now, not disk compression. One power outage and you'll have to reinstall Arch!

Am I missing something? I seem to have a btrfsfsck... haven't needed to use it yet...

# whereis btrfsck
btrfsck: /usr/bin/btrfsck /usr/share/man/man8/btrfsck.8.gz

for some reason it's fsck isn't picked up when I do a mkinitcpio...

# mkinitcpio -p linux
==> Building image from preset: 'default'
  -> -k /boot/vmlinuz-linux -c /etc/mkinitcpio.conf -g /boot/initramfs-linux.img
==> Starting build: 3.2.12-1-ARCH
  -> Parsing hook: [base]
  -> Parsing hook: [udev]
  -> Parsing hook: [autodetect]
  -> Parsing hook: [pata]
  -> Parsing hook: [scsi]
  -> Parsing hook: [sata]
  -> Parsing hook: [filesystems]
  -> Parsing hook: [usbinput]
  -> Parsing hook: [btrfs]
  -> Parsing hook: [btrfs_advanced]
  -> Parsing hook: [fsck]
==> ERROR: file not found: `fsck.btrfs'
==> WARNING: No fsck helpers found. fsck will not be run on boot.
==> Generating module dependencies
==> Creating gzip initcpio image: /boot/initramfs-linux.img
==> Image generation successful
==> Building image from preset: 'fallback'
  -> -k /boot/vmlinuz-linux -c /etc/mkinitcpio.conf -g /boot/initramfs-linux-fallback.img -S autodetect
==> Starting build: 3.2.12-1-ARCH
  -> Parsing hook: [base]
  -> Parsing hook: [udev]
  -> Parsing hook: [pata]
  -> Parsing hook: [scsi]
  -> Parsing hook: [sata]
  -> Parsing hook: [filesystems]
  -> Parsing hook: [usbinput]
  -> Parsing hook: [btrfs]
  -> Parsing hook: [btrfs_advanced]
  -> Parsing hook: [fsck]
==> Generating module dependencies
==> Creating gzip initcpio image: /boot/initramfs-linux-fallback.img
==> Image generation successful

.:B:. · 2012-03-25 00:01:09

hadrons123 wrote:

Oracle declared btrfs to be stable few days ago.

Oracle says so many things...

hadrons123 · 2012-03-25 01:31:32

==> ERROR: file not found: `fsck.btrfs'

I had this error too. But didnt know how to deal with that, and installed the OS in ext4.

Avi Miller · 2012-03-25 09:55:54

DSpider wrote:

They should focus on implementing an fsck and a recovery tool first. That's the biggest drawback from using btrfs right now, not disk compression.

We have both in btrfs already: the repairing version of btrfsck is in Chris' git repo and is included with btrfs-progs on Oracle Linux 5 and 6. Likewise, we now have both a read-only recovery tool that can copy data off a damaged btrfs volume, as well as a recovery mount option (mount -o recovery) that will back-walk the btrfs b-trees to find a stable, consistent filesystem.

Avi Miller · 2012-03-25 10:02:30

*nixer wrote:

I'm reinstalling Arch after finally receiving a replacement hard-drive. I'm considering holding off creating a Btrfs for / until the "snappy" compression algorithm becomes available.

Is there a particular reason you're waiting for Snappy? Keep in mind that you can actually change compression algorithms on-the-fly, i.e. start with LZO now and switch to Snappy compression later. Obviously older files that are compressed will remain LZO, but new files and modified files will be recompressed with Snappy.

*nixer · 2012-03-25 14:14:38

I'm running an old PC with no hope of upgrade for now with the bottleneck being a Pentium 4 cpu.

This was based off a completely subjective feel, and while I didn't actually do any benchmarks, I thought the following.

- Uncompressed Btrfs performed better on desktop tasks than Ext4 did.
- Btrfs with lzo compression created a noticible lag time when loading apps.

I was hopingthe snappy compression would create a nice compromise while trying to save as much space as possible.

fowler · 2012-03-25 23:33:45

Is btrfs compression even beneficial if you have an ssd that already does compression (like intel ssd's)?

graysky · 2012-03-28 18:32:41

Avi Miller wrote:

DSpider wrote:
They should focus on implementing an fsck and a recovery tool first. That's the biggest drawback from using btrfs right now, not disk compression.
We have both in btrfs already: the repairing version of btrfsck is in Chris' git repo and is included with btrfs-progs on Oracle Linux 5 and 6. Likewise, we now have both a read-only recovery tool that can copy data off a damaged btrfs volume, as well as a recovery mount option (mount -o recovery) that will back-walk the btrfs b-trees to find a stable, consistent filesystem.

Avi - I can't seem to locate the repo to which you refer. I did find the following, but this hasn't seen an update in 6 months. Can you post the url? Would love to get my hands on the fsck util

https://github.com/chrismason

Avi Miller · 2012-03-28 20:13:52

graysky wrote:

Avi - I can't seem to locate the repo to which you refer.

https://git.kernel.org/?p=linux/kernel/ … ads/master

This is actually the version of btrfs-progs we've released as part of the UEK2 production release on Oracle Linux. Chris merged it across this morning/evening depending on your timezone.

Last edited by Avi Miller (2012-03-28 20:17:35)

fowler · 2012-03-28 21:04:40

I have an intel 520 (cherryville) that I was thinking about installing arch with btrfs compress=lzo, would there be any benefit to this or would I be defeating the purpose of the on ssd compression. I tried the install a few times with and without, it took a long time to open an encrypted document and some vm's seemed laggy. It was less so without, but I'm not sure that was a misconfiguration or not. I even tried a gentoo install with out it and it was huge on the disk, I might try it with compression to see what difference it would make.

Besides my little experience there doesn't seem to be a lot of definitive info about compression with btrfs on an ssd that does compression, whether it helps or not.

DSpider · 2012-03-29 11:55:20

Using compression for an SSD means less data to be written and thus, less wear on the cells. But compressing an already compressed file could result in a slightly larger file (not to mention a higher CPU involvement in the process) - which could very well be pointless.

But I think that this discussion is outside the scope of this thread.

If your SSD comes with some form of hardware compression, maybe you can disable it with a firmware tool, setting, reflash, something and let the OS compress them with a better algorithm/method.

Arch Linux

#1 2012-03-23 13:18:09

Btrfs root install: Is snappy compression available in Arch?

#2 2012-03-23 19:24:39

Re: Btrfs root install: Is snappy compression available in Arch?

#3 2012-03-23 19:56:41

Re: Btrfs root install: Is snappy compression available in Arch?

#4 2012-03-23 20:54:33

Re: Btrfs root install: Is snappy compression available in Arch?

#5 2012-03-24 01:15:13

Re: Btrfs root install: Is snappy compression available in Arch?

#6 2012-03-24 23:14:58

Re: Btrfs root install: Is snappy compression available in Arch?

#7 2012-03-25 00:01:09

Re: Btrfs root install: Is snappy compression available in Arch?

#8 2012-03-25 01:31:32

Re: Btrfs root install: Is snappy compression available in Arch?

#9 2012-03-25 09:55:54

Re: Btrfs root install: Is snappy compression available in Arch?

#10 2012-03-25 10:02:30

Re: Btrfs root install: Is snappy compression available in Arch?

#11 2012-03-25 14:14:38

Re: Btrfs root install: Is snappy compression available in Arch?

#12 2012-03-25 23:33:45

Re: Btrfs root install: Is snappy compression available in Arch?

#13 2012-03-28 18:32:41

Re: Btrfs root install: Is snappy compression available in Arch?

#14 2012-03-28 20:13:52

Re: Btrfs root install: Is snappy compression available in Arch?

#15 2012-03-28 21:04:40

Re: Btrfs root install: Is snappy compression available in Arch?

#16 2012-03-29 11:55:20

Re: Btrfs root install: Is snappy compression available in Arch?

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