btrfs as default filesystem for F22?

[Gene Czarcinski]

On 10/08/2014 02:28 AM, Thorsten Leemhuis wrote:
> Thorsten Leemhuis wrote on 08.10.2014 07:52:
>> Josh Boyer wrote on 07.10.2014 21:15:
>>> On Tue, Oct 7, 2014 at 2:24 PM, Josef Bacik <josef at toxicpanda.com> wrote:
>>> […]
>>>>> I think the point is somewhat valid though. To just keep repeating the
>>>>> mantra 'its not ready' is not going to make it any more ready. If suse
>>>>> can identify a stable subset of btrfs features and use it as their
>>>>> default file system with those restrictions, why can't we do the same ?
>>>>> The approach makes sense to me, at least...
>>>> Because they still have the support staff for when users don't listen,
>>>> Fedora doesn't.
>>> As an aside, I looked at their 3.16.2-1.1.gdcee397 kernel-source SRPM.
>>> I can't find any patches that limit btrfs usage.  I could totally be
>>> wrong, but if someone knows of a patch that limits the features please
>>> point me to it.
>> Due to a coincidence I yesterday took a quick look myself and didn't
>> spot anything. But in case you haven't looked further: I found one in
>> the SLE-Kernels:
>>
>> http://kernel.opensuse.org/cgit/kernel-source/tree/patches.suse/btrfs-8888-add-allow_unsupported-module-parameter.patch?h=SLE11-SP3
>> http://kernel.opensuse.org/cgit/kernel-source/tree/patches.suse/btrfs-8888-add-allow_unsupported-module-parameter.patch?h=SLE12
> BTW & TWIMC, their solution to problems like this
> http://aseigo.blogspot.de/2014/09/btrfs-rebalancing.html (ran into this
> myself yesterday) seems to be a package called btrfsmaintenance that was
> introduced a few days ago. Quoting
> http://article.gmane.org/gmane.linux.suse.opensuse.devel/59787/
> """
>> From: David Sterba <dsterba <at> suse.cz>
>> Subject: Introduce btrfsmaintenance package to Factory
>> Newsgroups: gmane.linux.suse.opensuse.devel
>> Date: 2014-10-06 15:40:37 GMT (1 day, 14 hours and 40 minutes ago)
>>
>> Hi,
>>
>> let me introduce a new package that supplements the btrfs filesystem and aims
>> to automate a few maintenance tasks. This means the scrub, balance, trim or
>> defragmentation. The package comes from SLE12 where btrfs is going to be the
>> default filesystem as well.
>>
>> Each of the tasks can be turned on/off and configured independently. The
>> default config values were selected to fit the default installation profile.
>>
>> * scrub - go through all medatada/data and verify the checksums, default period
>> is one month
>>
>> * balance - the balance command can do a lot of things, in general moves data
>> around in big chunks, here we use it to reclaim back the space of the
>> underused chunks so it can be allocated again according to current needs
>>
>> The point is to prevent some corner cases where it's not possible to eg.
>> allocate new metadata chunks because the whole device space is reserved for all
>> the chunks, although the total space occupied is smaller and the allocation
>> should succeed.
>>
>> * trim - run TRIM on the filesystem using the 'fstrim' utility, makes sense for
>> SSD devices.
>>
>> * defrag - run defrag on configured directories. This is for convenience and
>> not necessary.
>>
>> There's a separate defragmentation task that happens automatically and
>> defragments only the RPM database files in /var/lib/rpm. This is done via a
>> zypper plugin and the defrag pass triggers at the end of the installation.
>>
>> This improves reading the RPM databases later, but the installation process
>> fragments the files very quickly so it's not likely to bring a significant
>> speedup here.
>>
>> Cron takes care of periodic execution of the scripts, but they can be run any
>> time directly from /usr/share/btrfs/maintenance/, respecting the configured
>> values in /etc/sysconfig/btrfsmaintenance.
>>
>> If the period is changed manually, the cron symlinks have to be refreshed, use
>> "systemctl restart btrfsmaintenance-refresh" (or the
>> "rcbtrfsmaintenance-refresh" shortcut). Changing the period via yast2 sysconfig
>> editor triggers the refresh automatically.
>>
>> The project lives in obs://filesystems/btrfsmaintenance and I'm going to submit
>> it to Factory.
>>
>> I'd like to ask volunteers to give it some testing.  Feedback is welcome.
>>
>> Thanks,
>> David
> """
> The package in the opensuse obs:
> https://build.opensuse.org/package/show/filesystems/btrfsmaintenance
>
> Seems to mostly consist of shell scripts.
>
> CU
> knurd
The new btrfsmaintenance package looks like something that should be 
added to Fedora regardless of btrfs status ... again this is something 
that Fedora could do which would make things easy to use and promote 
knowledgeable use of BTRFS without making it default. It is the 
"support/infrastruction" packages that need more attention and the the 
btrfs-kernel or btrfs-progs themselves.

Gene