One exception: In periods of extremely heavy read activity, writes do get choked. And also vice versa. I can strongly feel this when doing some major dd'ing, which probably won't simulate your load at all. The deadline I/O scheduler did help out, though, for some reason. (my imagination?)

 

I agree with this statement. I ran reiser4 on 2 of my system. In the 2.6.8 days, one reiser4 volume unexpectedly started exhibiting random hangs. fsck didn't find anything, and the hangs were VERY hard to reproduce, if at all. (sometimes APT's building dependencies tree would spark it, but it's like a .1% chance). The other one, reiser4's working fine ( 2.6.11.10), but I really miss xattr (Beagle). Oh well, can't have everything.