On Tue, Apr 11, 2017 at 07:47:46PM +0200, David Sommerseth wrote:
> 
> ... newer file systems have more bugs than older file systems. ...
>

I do not think that is necessarily true.

Newer filesystems have consistly added functionality to detect
and prevent data corruption, to preserve and ensure data integrity.
It is hard to quantify how this is offset by the (unmeasureable)
increase in number of bugs.

The 1st generation filesystems are quite well debugged (msdos/fat/vfat,
ext2/3/4) but do not have any features to preserve data integrity.

The 2nd generation filesystems (like SGI XFS) added some built-in data
integrity checks (the first release of XFS did not even have an fsck
because "it will never corrupt". the second release added an fsck,
because bad hardware does corrupt anything).

But they lack data checksums and "online fsck" features - you have to take
the server offline to confirm filesystem consistency.

They also tend to have bad interaction with the RAID layers (all the stripes
and stuff has to line-up correctly or performance is very bad).

The 3rd generation filesystems (zfs, btrfs) add data checksums, online-fsck,
"integrated raid".

So the choice is between you saying "I trust XFS, I never fsck it",
and me saying "I do not trust ZFS, I do not trust the hardware, I run
ZFS scrub daily, I have backups, I have archives".

>
> Consider the
> amount of users using ext4 and XFS, vs btrfs/zfs ... and in which of
> these groups do you hear more about users experiencing data loss?
> 

Ah, the science of it. "which do I hear more...". There is a difference
between the actual number of faults, reported number of faults
and "I read about it on slashdot" number of faults.

>
> And I do care about data loss.  Because if that happens, I need to start
> running restore jobs from backups and recover files and file systems.
> So having a stable and rock solid file system reduces the chances of
> extra work for me.  And my users are much more happy too.
> 

I think it is a good thing if you have to restore files from backup and archive
at least once a year. How else do you know your backups actually work?

-- 
Konstantin Olchanski
Data Acquisition Systems: The Bytes Must Flow!
Email: olchansk-at-triumf-dot-ca
Snail mail: 4004 Wesbrook Mall, TRIUMF, Vancouver, B.C., V6T 2A3, Canada