What is the reason for having HTREE disabled? From the descriptions below, it would seem that even a reasonable sized GroupWise system would start to choke with HTREE disabled since you're easily going to have more than 5000 files per directory in the offiles folders. Based on this fact, EXT3 would only be a viable option if in fact you could enable HTREE. Otherwise Reiser would be the preferred choice for performance, though the future of REISER is now in question.
Please clarify. What is the optimal configuration on a SLES only (No OES) system?
Most popular Linux file system, limited scalability in size and number of files
POSIX extended access control
EXT3 file system is a journaled file system that has the greatest use in Linux today. It is the "Linux" File system. It is quite robust and quick, although it does not scale well to large volumes nor a great number of files. Recently a scalability feature was added called htrees, which significantly improved EXT3's scalability. However it is still not as scalable as some of the other file systems listed even with htrees. It scales similar to NTFS with htrees. Without htrees, EXT3 does not handle more than about 5,000 files in a directory.
Best performance and scalability when number of files is great and/or files are small
POSIX extended access controls
The Reiser File System is the default file system in SUSE Linux distributions. Reiser FS was designed to remove the scalability and performance limitations that exist in EXT2 and EXT3 file systems. It scales and performs extremely well on Linux, outscaling EXT3 with htrees. In addition, Reiser was designed to very efficiently use disk space. As a result, it is the best file system on Linux where there are a great number of small files in the file system. As collaboration (email) and many web serving applications have lots of small files, Reiser is best suited for these types of workloads.