[Discuss] BTRFS, ZFS, XFS .... Confused!!

[Alan W. Irwin]

On 2014-10-28 20:44-0700 Cy Schubert wrote:

> In message <5450034E.50607 at shaw.ca>, John Blomfield writes:
>> Following the recent comments on this list about Bit Rot and file
>> systems I have been doing a little reading about the changes that are
>> coming. Most of the discussion I confess is way above my head unless I
>> do a lot more reading and studying. However, I would like to achieve
>> some clarity over the short term until I have time and inclination to
>> delve deeper myself.
>
> Generally the enterprise distro RHEL and its cousins -- CentOS, Oracle
> Unbreakable Linux, and Scientific Linux -- have put filesystems on LVM
> (Logical Volume Manager), a rip off of LVM in HP/UX. It eases the pain of
> partitioning.
>
>>
>> My preferred Distro is OpenSuse and the latest version 13.2 is due to be
>> released in 6 days and I will no doubt be giving it a test run in the
>> next few weeks when the teething troubles have been sorted out with the
>> normal early updates. Until now OpenSuse including the present 13.1,
>> BTRFS has been an option during installation and referred to as "beta"
>> but with 13.2 BTRFS is now the default file system but countless other
>> file systems are available. Amongst these on OpenSuse are ZFS and XFS -
>> what to do? Will any of these new file systems affect any applications
>> or the system as a whole and prevent some apps running or perhaps limit
>> their function?
>
> BTRFS is the Linux answer to ZFS, which is not GPL compatible. I've used
> BTRFS. It's klunky, definitely not a breeze like ZFS is. You could use ZFS
> under fuse but given the performance hit under fuse it's not worth it.
> Personally, I'd stick with LVM, I don't think BTRFS is production ready.

@ Cy: LVM is not a file system.  Instead, it is an optional layer that
provides logical partitions that is installed on top of actual
hardware partitions.  Also, it is clear that OpenSUSE does feel that
BTRFS is production ready.  If they make a mistake about that, it is a
huge hit for their distro and their personal reputations so I assume
they did a lot of testing and due diligence before making this huge
decision.

@ John: File systems like BTRFS and ext4 (probably the
previous SuSe default filesystem) are installed either on hardware
partitions or logical partitions.  Then your files are stored on the
filesystem, and in the normal course of events you should not
even be noticing your filesystem (except for the case of snapshots).

BTRFS has been the expected successor to ext4 on Linux for at least 5
years now (even by the principal developer of ext4).  See the remarks
in <http://en.wikipedia.org/wiki/Btrfs>.  However, ext4 has been 
"good enough" and zillions of users had little trouble with ext4.
Thus, many distributions stuck with ext4 as the default despite lack
of certain killer features (that BTRFS has) such as snapshots.

Thus, it is extremely interesting that OpenSUSE is now moving to BTRFS
as the default which is a huge vote of confidence for that filesystem
(see remarks above). Since most users take the default, that is likely
the first huge deployment of BTRFS by a major distro which is likely
guaranteed to find the final few bugs (if any) in BTRFS.  So if you
want to be part of that huge mass software experiment and trust the
OpenSUSE developers have done their homework, then take the default,
but otherwise if you want to be supercareful I would stick with your
current filesystem (likely ext4) until the next release of OpenSUSE.

For Debian, I have always just taken the default filesystem being
offered.  But those distro developers are notoriously conservative so
they stuck with ext3 somewhat longer then other distros before moving
to ext4, and I expect they will likely also be the last major distro
to offer BTRFS as the default filesystem.

Alan
__________________________
Alan W. Irwin

Astronomical research affiliation with Department of Physics and Astronomy,
University of Victoria (astrowww.phys.uvic.ca).

Programming affiliations with the FreeEOS equation-of-state
implementation for stellar interiors (freeeos.sf.net); the Time
Ephemerides project (timeephem.sf.net); PLplot scientific plotting
software package (plplot.sf.net); the libLASi project
(unifont.org/lasi); the Loads of Linux Links project (loll.sf.net);
and the Linux Brochure Project (lbproject.sf.net).
__________________________

Linux-powered Science
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