btrfs as default filesystem for F22?

[Steven Whitehouse]

Hi,

On 03/10/14 07:42, Juan Orti Alcaine wrote:
> El 2014-10-03 05:31, Andre Robatino escribió:
>> openSUSE 13.2, scheduled for release in November, will have btrfs as the
>> default filesystem. What are the chances that F22 will follow suit, 
>> assuming
>> openSUSE has no major problems with it?
>>
>> https://news.opensuse.org/2014/09/22/
>
> I've been using btrfs for a while now, and while the kernels 3.15.x 
> and 3.16.{0,1} have been problematic, the latest one is working smooth 
> again.
>
> Anyway, I recommend using only the core features (snapshots, raid1, 
> scrubs, balances, cp --reflink, etc...), because others have many 
> quirks, like send/receive which get corrupted from time to time, raid 
> 5/6 which is work in progress, or problems related to low free space.
>
> To implement btrfs as the default, grubby must support to install 
> /boot on btrfs (bug #1094489). I have to run grub2-mkconfig with every 
> kernel update to circumvent this problem.
>
> It is also worth considering adding some scheduled tasks for 
> maintenance, like rebalances, or scrubs.
>

I think "problems related to low free space" is a big issue for a 
default file system. If users have a bad experience due to a problem on 
the default file system, then that will very likely reflect on their 
feelings about Fedora as a whole, so it is vitally important that 
whatever fs is the default is as stable as possible.

It is possible to already do all of the things (and more) which you've 
listed under "core features" using LVM/dm/md too, with the exception of 
cp --reflink, so that it wouldn't result in a big difference in 
functionality unless and until the more experimental (for want of a 
better term) btrfs features mature. There is also currently a much 
greater developer community around LVM/dm/md than there is around the 
same (volume level) features in btrfs, and LVM/dm/md supports a wider 
range of functionality.

I should also add (just in case anybody gets the wrong idea!) that I 
think it should definitely be made as easy as possible for anybody who 
wants to evaluate running btrfs on Fedora, but it is far too early to 
make it the default yet,

Steve.