Ext3 users - Jul 2001 - To ext3 or not to ext3?

I'm in the process of building a home file server and am of course going
to use Linux 2.4 (2.4.6 for now...).  I'm waffling between resierfs and
ext3.  I've read the ext3 page and some of the mailing list archives but
have a few questions remaining.  (I apologize in advance if they are
redundant.)

Are there any known issues with:

	- LVM

	- LVM snapshots (more on that in a sec)

	- Software RAID 5

	- knfsd (including NFS v.3 support)

The hardware will be a vanilla Pentium III with a bunch of IDE drives.

I think that ext3 support for LVM snapshots is still in the works... I'm
okay with not using them until they work, but would still like to plan
ahead and put the filesystem on an LVM volume now.  In general I don't
mind foregoing features for now if I can enable them later on without
losing data or having to rebuild from scratch.

Also, my understanding from the various benchmarks posted around is that
ext3 and reiserfs are neck-and-neck in terms of speed.  Reiserfs may have
a slight advantage but I'd rather put my trust in ext3 given past
experiences.  Does that sound reasonable and accurate?

Thanks in advance for the info!

	-Joel

Hi,

On Tue, Jul 10, 2001 at 11:55:26AM -0600, Joel Votaw wrote:
 
> Are there any known issues with:
> 	- LVM
> 	- LVM snapshots (more on that in a sec)
> 	- Software RAID 5
> 	- knfsd (including NFS v.3 support)
No.  It should all work --- if it doesn't, please let me know!

However, we are getting reports of lockups under severe VM load.  It
seems reproducible on ext2 too (especially on HIGHMEM machines), but
ext3 drives the VM a bit harder by requiring more memory allocations
internally for some operations and by imposing extra synchronisation
between filesystem syscalls.

I'm still hunting this --- it looks like ext3 is just making the VM
suffer more, rather than producing any genuine new bugs.  There are
still lots of patches going into the 2.4 core VM to try to help.
> I think that ext3 support for LVM snapshots is still in the works...
I'm
> okay with not using them until they work, but would still like to plan
> ahead and put the filesystem on an LVM volume now.
They should work straight away, although it's not something I've
played with myself.
> Also, my understanding from the various benchmarks posted around is that
> ext3 and reiserfs are neck-and-neck in terms of speed.  Reiserfs may have
> a slight advantage but I'd rather put my trust in ext3 given past
> experiences.  Does that sound reasonable and accurate?
Sort of.  ext3 seems to suffer less from fragmentation over time and
performs better for some large-file tasks such as database file
access; reiserfs is obviously known to be faster on huge directories
and has better efficiency on small files.  However, most normal users
probably won't notice much difference between them.

Cheers,
 Stephen