State of BTRFS

State of BTRFS

[Steve Keller]

What is the state of btrfs concerning stability and reliability?

Is it safe to my /home file system on btrfs?  I need no RAID,
currently, as I have mdraid with LVM on top of that already, and I
have an LVM volume for /home.  But I do like snapshots and would
probably use them quite a lot.

Currently, I have ext4 for /home but I consider switching to btrfs.
But I want to be really sure not to loose data or otherwise have
to repair the file system.

Steve

Re: State of BTRFS

[A L]

On 2020-11-26 18:32, Steve Keller wrote:
> What is the state of btrfs concerning stability and reliability?
I think that the general opinion is that Btrfs profiles 
single,dup,RAID0,RAID1,RAID10,RAID1c34 are safe to use. RAID5/6 has 
issues and is not recommended unless you are experienced with Btrfs.

> Is it safe to my /home file system on btrfs?  I need no RAID,
> currently, as I have mdraid with LVM on top of that already, and I
> have an LVM volume for /home.  But I do like snapshots and would
> probably use them quite a lot.
In this configuration, Btrfs will be able to detect corruptions (bit 
files, faulty data, etc) but be able to repair it. Depending on your 
needs for LVM it may be better to run Btrfs RAID1 so you can utilize the 
full features of Btrfs that protects you from corrupt data.

You should read up on the risks with using volume managers underneath 
Btrfs. For example you can have issues if you use LVM snapshots.

>
> Currently, I have ext4 for /home but I consider switching to btrfs.
> But I want to be really sure not to loose data or otherwise have
> to repair the file system.
>
> Steve
>
Should not be less safe than copying your files over to the new Btrfs 
volume. I would not use btrfs-convert to convert the ext4 to Btrfs. 
Instead set up a new Btrfs volume and copy the files there.

Re: State of BTRFS

[Hugo Mills]

On Thu, Nov 26, 2020 at 06:32:59PM +0100, Steve Keller wrote:
> What is the state of btrfs concerning stability and reliability?
> 
> Is it safe to my /home file system on btrfs?  I need no RAID,
> currently, as I have mdraid with LVM on top of that already, and I
> have an LVM volume for /home.  But I do like snapshots and would
> probably use them quite a lot.
> 
> Currently, I have ext4 for /home but I consider switching to btrfs.
> But I want to be really sure not to loose data or otherwise have
> to repair the file system.

   In general, it's in pretty good shape. Avoid parity RAID
(especially for metadata), and qgroups. Other than that, the FS itself
should be good.

   The main concern these days is broken hardware: Disks that have
poor cache behaviour in the face of power failure, or that simply lie
about stuff having reached permanent storage, or have other serious
firmware bugs. These can lead to the (generally unrecoverable) transid
error state (see the FAQ [1] for a detailed explanation).

   Hugo.

[1] https://btrfs.wiki.kernel.org/index.php/FAQ#What_does_.22parent_transid_verify_failed.22_mean.3F

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