Re: Status of ReiserFS + Journalling

[Andi Kleen]

On Wed, Oct 04, 2000 at 01:42:46AM -0600, Andreas Dilger wrote:
> Magnus Naeslund writes:
> > The storage will be exported via ftp, samba, nfs & cvs.
> > I will patch the selected kernel to support LFS and LVM, and the filesystem
> > will run on that.
> > 
> > I am very interested in ReiserFS, and success/failure stories about it.
> 
> You really need to watch out when using ReiserFS as an NFS server.  There
> are patches to NFS in order to run on ReiserFS.  There were also problems
> (they may be fixed now) that force the NFS clients to be Linux only.

I never knew of any problems that didn't affect linux clients too (and 
I did most of the NFS patches) If you know any please let me know.

> 
> You should ask the reiserfs mailing list for outstanding problems.  As
> far as LVM is concerned, I don't think there is a problem, but watch out
> for software RAID 5 and journalling filesystems (reiser or ext3, at least
> under 2.2) - it can have problems if there is a disk crash.

It is not inherent to journaling file systems, linux software raid  5
can always corrupt your data when you have a system crash with a disk
crash (no way to write stripe sets atomically and half writen strip sets
usually give random data for any crashed block in it when xored against parity) 

Given that 2.4 should be safe.

In this case "safe" just means that you don't need a fsck to be sure that
the metadata is consistent -- data is never guaranteed to be consistent 
unless you have applications that use fsync/O_SYNC properly (=basically do 
their own journaling) 

So overall I would not be worried too much, it isn't much worse with a 
journaled fs than it is without it.

-Andi