Data Loss

Data Loss

[Dipl.-Ing. Michael Niederle]

Hi!

It's absolutely strange: nilfs seems to crash during idle times!

This time everything seemed to be fine when I returned to my PC after several
hours. Astonishingly my pen drive's LED reported heavy activity despite the
fact that there was nothing to do. I have a script that detects recently
changed files. This script reported that not a single file had been changed
during the last hour!

After a reboot the system got stuck when trying to pivot_root to the
nilfs-root-file-system (no problem mounting it). An analysis showed that
several files had been destroyed. The stat-utility showed the file type
"weird". ^^

I also mounted some elder checkpoints. They now had defect files, too.

In my opinion the cleaner daemon is causing all these problems but - as always -
I might be wrong.

As to my knowledge there is currently no way to repair a nilfs-file-system?

Greetings, Michael

Re: Data Loss

[Ryusuke Konishi]

Hi,
On Fri, 12 Jun 2009 01:10:57 +0200, "Dipl.-Ing. Michael Niederle" wrote:
> Hi!
> 
> It's absolutely strange: nilfs seems to crash during idle times!
> 
> This time everything seemed to be fine when I returned to my PC after several
> hours. Astonishingly my pen drive's LED reported heavy activity despite the
> fact that there was nothing to do. I have a script that detects recently
> changed files. This script reported that not a single file had been changed
> during the last hour!

I think the activity is created by the garbage collector.  Note that
Nilfs GC works background and it wakes up after protection period of
checkpoints is expired.

Probably, the delay time you have experienced is the protection period.

> After a reboot the system got stuck when trying to pivot_root to the
> nilfs-root-file-system (no problem mounting it). An analysis showed that
> several files had been destroyed. The stat-utility showed the file type
> "weird". ^^

Grr, GC problem?
 
> I also mounted some elder checkpoints. They now had defect files, too.
>
> In my opinion the cleaner daemon is causing all these problems but -
> as always - I might be wrong.
>
> As to my knowledge there is currently no way to repair a nilfs-file-system?

Uum, yes. Only we can do is finding clean checkpoint.

> Greetings, Michael

Regards,
Ryusuke Konishi