On Mon, 17 Jul 2000, Brian J. Murrell wrote:
> I have recently purchased a RaidZone (http://www.raidzone.com/) disk
> array. The hardware in this unit seems pretty good but their knowlege
> of Linux, NFS, and it's filesystems seems to suck rocks. They don't
> seem to talk with any authority on any of these technologies. I am
> hoping you will indulge my query.
>
> The main issue I guess is with ReiserFS and KNFS. Their kernel supports
> KNFS and ReiserFS but they don't enable KNFS on these units. Instead
> they use the older usermode NFS due to "performance problems with
> ReiserFS and KNFS".
>
> Are these claims of bad performance of ReiserFS with KNFS true?
> What is the issue?
Yes, they are true. The issue is that reiserfs needs 64 bits of
information to find a file on disk, and NFS only gives us 32 bits. If the
inode is in cache already, things are fine. But if the inode has left
cache, and an NFS client tries to do an operation on it, reiserfs has to
guess the remaining 32 bits, which is not at all speedy.
> Will it be solved any time soon?
Andi Kleen has patches for both usermode and kernel nfs servers that make
them behave better with reiserfs. The knfsd patches are not as well
tested, the usermode ones have been used at suse for a while now.
ftp.suse.com/pub/people/ak/nfs
-chris
