Robert; These two articles explain some of the major benefits of ReiserFS. While these are not too old, the issues raised here have been fixed or resolved in ReiserFS, specifically the LFS and the Quotas. We have worked extensivley with ReiserFS here, and have had the good fortune of collaboration with Hans (Lives here in Oakland, always nice) and Chris Mason, the Journaling code developer.
While we have not seen the 15 times performace, ReiserFS generally performs better than anything we have seen on Linux, z or Intel. Any Journal performance hits are easily taken care of with SSD devices to relocate the journal, but that is in the most Highest Volume systems, and would not imagine that to be everyday environments. The only other issue I can warn of is that non-journaled systems are never used in the Sendmail deployments we do, as the Queues or mailstores can become corrupt, especially with the large Cache on today's controllers. EXT2 does not fsync or dirsync correctly, we had to place patches into 8.12 code base for this problematic issue (people that use EXT2 anyway). EXT3 will have the same set of problems, infact I was just doing studies on this today and the 180 fsync, well in this case we were looking at HA and remounts, not pretty if you have a 500gig datastore that is say 181 days uptime and you switch nodes with a SCSI reset and remount, fsync! http://www-106.ibm.com/developerworks/library/l-fs.html http://www-106.ibm.com/developerworks/library/l-fs2.html Clip in one of the above, keep in mind avg message sizes that are "small": ---SNIP--- Well, that's the theory. But how good is ReiserFS' small file performance in practice? Amazingly good. In fact, ReiserFS is around eight to fifteen times faster than ext2 when handling files smaller than one k in size! Even better, these performance improvements don't come at the expense of performance for other file types. In general, ReiserFS outperforms ext2 in nearly every area, but really shines when it comes to handling small files. ---SNIP--- Regards, Jon Jon R. Doyle Sendmail Inc. 6425 Christie Ave Emeryville, Ca. 94608 (o_ (o_ (o_ //\ (/)_ (\)_ V_/_ On Tue, 23 Apr 2002, Robert Werner wrote: > Hi Jon, > > > > Significant performance increases will be seen using the ReiserFS for > > Queues dirs due to the small random file counts. You can find all kinds of > > info on ReiserFS on the IBM site. The other thing you would really want to > > investigate is Sendmail 8.12. Yes, Yes, not just another "go to the new > > rev" 8.10 actually performs better in some cases, 8.12 has this > > performance plus advantages in the allocation of processes and queue > > definition. I do know that SuSE builds of 8.12 are available, have not > > checked right away on zSeries. You can always use source. > > > > We have also seen large performance gains on 2.4.18, especially with the > > SuSE patch from Andrea (VM33). > > > > Up to now I thought that every filesystem with journaling lowers disk > performance ? The journaling function produces additional CPU load and > i/o's. So I'm suprised that ReiserFS should be faster than ext2. Let's see > if I find time to try it out. > > I just read the list of new features from sendmail 8.12. Seems that for our > purpose - a smtp-relay that is mx-backup for several domains - upgrading to > 8.12.3 could result in much better performance. I think it's worth building > it on the zSeries. > > > Thanks, > > Robert. >
