Thank you very much for your feedback so far!

Kerin Millar wrote:
> For this reason, and because I believe that the stability of reiserfs
> was improved drastically in later revisions of the 2.4 kernel, I would
> urge that you consider using a modern 2.4 kernel and the latest reiserfs
> tools if possible!

I don't want to describe why we are still using such an outdated system :-) 
but we will move to Gentoo with a current 2.6.x kernel and reiser4 soon. I 
just wanted to know if this will eliminate the problem once and for all - at 
least in theory - because of the new concepts in reiser4 (atomic 
transactions).  

------

Christian Mayrhuber wrote:
> I'd suggest to do the following for pull the plug scenarios on productive
> systems with reiserfs:

> 1) Disable write caching for ide drives with "hdparm -W 0 /dev/hdX"
> � �This is the most important thing to do.

Will this really help to protect against partially written sectors and from 
there resulting read-errors (If a disk loses power while writing a sector the 
CRC-Check will fail and the disk reports an read-error that's not caused by a 
real hardware defect)? Changing the write cache strategy just "moves" the 
problem "in time" - maybe the propability that something happens is lower, 
because the amount of data that gets written at a certain point of time is 
smaller. 

> 4) If you want to prevent data corruption and not just filesystem
> � �corruption, use a recent 2.6.x kernel which incoporates Chris Mason's
> � �data logging patches.
> � �Alternatively you could use a newer SuSE which has the data logging
> � �patches in the 2.4 kernel series, too. Maybe the installation of a
> � �a newer 2.4.x kernel rpm from ftp.suse.com will work for you.

> As reiser4 is atomic in it's operations it should protect your data even 
more 
> than ext3/reiserfs with the data=journal mount option, unless you don't have
> write cache for ide drives enabled. Reiser4 is still beta.

I am not concerned about the current beta quality, we will migrate early next 
year and someday the bugs will be fixed. Updating a SuSE system is quite a 
pain I experienced (without reinstalling), it will be easier with Gentoo to 
keep a reasonable current system.

> Since 2.6.9 the write barrier patches are in the kernel. These should
> protect better from data loss with disks that have write caching enabled.
> The only two filesystems supporting write barrier are ext3 with the mount
> option "barrier=1" and reiserfs with the mount option "barrier=flush".

Our problem is not loss of (user) data. If someone pulls the plug before all 
unsaved data is written or before the write cache is flushed - I don't care. 
But it would be nice if the system would boot again... and all system files 
are sane. As I understand it, reiser4 recognizes if a certain transaction was 
completed successfully. But will it fix a partially written sector?

Bye,

Bernhard

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