You are not logged in.

#1 2013-07-15 14:57:58

bcarnazzi
Member
From: Ile de la Réunion
Registered: 2012-01-28
Posts: 14
Website

[SOLVED] Btrfs and skinny extends

Hi,

I've read that with linux 3.10, Btrfs now has skinny updates, which seems to be great : http://www.phoronix.com/scan.php?page=n … px=MTM2OTI
I have a USB hard drive with Btrfs on it for testing this, but my btrfstune program doesn't support the "-x" option :

[bcarnazzi@armaghast ~]$ btrfstune --help
btrfstune: invalid option -- '-'
usage: btrfstune [options] device
	-S value	enable/disable seeding
	-r 		enable extended inode refs

I use btrfs-progs 0.20rc1.2-1 and linux-ck-core2 3.10.1-2 from repo-ck

Anyone can help ?

Thank you,

Bruno.

Last edited by bcarnazzi (2013-07-15 15:39:01)

Offline

#2 2013-07-15 15:04:41

WonderWoofy
Member
From: Los Gatos, CA
Registered: 2012-05-19
Posts: 8,412

Re: [SOLVED] Btrfs and skinny extends

Use the btrfs-progs-git from the AUR.  If you are going to be using btrfs, it is probably best to use the development progs anyway.  Btrfs has been moving so quickly in its development that even thought the btrfs-progs in the repos stays pretty up to date, it is not uncommon for new features that I am looking for to not be included in the btrfs-progs in the repos.

In any case, it probably makes sense to still have that version, as in [core] we still have Linux 3.9.9 (probably 3.9.10 soon), so this functionality is not yet necessary.

As a side note, I tried this already... I tried it as soon as I started using 3.10.  But when I turn the skinny extents on, the btrfs send/receive no longer works.  I'm not sure why, but this is how I back up my system, so I have reverted back to non-skinny extents, and am waiting for this issue to be sorted.  You should know that disabling skinny extents is not as simple as using btrfstune.  You have to move the data somewhere else temporarily, then recreate the filesystem. 

I went through the process of enabling and disabling a few times, thinking that I must just be doing something stoopid.  But it was consistent that the send/receive would stop working with "btrfstune -x <device>".  So I wait.

Offline

#3 2013-07-15 15:28:23

bcarnazzi
Member
From: Ile de la Réunion
Registered: 2012-01-28
Posts: 14
Website

Re: [SOLVED] Btrfs and skinny extends

I was not aware of the send/receive method for backing up. In fact, I'm mainly interested by the compression features of Btrfs. I use rsnapshot on top of it. But the send/receive method seems really cool : https://btrfs.wiki.kernel.org/index.php … tal_Backup

Thank you,

Bruno.

Offline

#4 2013-07-15 15:36:31

WonderWoofy
Member
From: Los Gatos, CA
Registered: 2012-05-19
Posts: 8,412

Re: [SOLVED] Btrfs and skinny extends

It is really really cool.  Since btrfs can keep track of just the changed portions between snapshots, it can therefore use this capability with send/receive to send incremental backups that link to the already received snapshots.  So unlike rsync, it is not comparing to determine what to send, it is simply sending what it knows to be differences.  It is very fast, and very efficient.

If you are satisfied with btrfs-progs-git as the answer to your question, then you should mark the thread as [Solved].  This can be done by editing the first post.  B aware too that btrfs-progs-git is pulling from Chris Mason's git repo.  But there are a couple others.  Josef Barik's is of particular interest, as his is more of a collection of patches being tested.  So often if you have something go awry, and you ask on the btrfs mailing list, they will ask you to try with Josef's btrfs-progs.

Offline

Board footer

Powered by FluxBB