I tried to sort out the "state of the art" several months ago, and it was like this:
There were serious problems w/ 8.1.5. There may have been some problems with 8.1.6.0. It looks like they were mostly sorted out with 8.1.6.2 (or .3? Never could get clear on exactly what the patch # was, have heard it named as both). Many of the problems are discussed in the ASJ article. I added a comment that the right way to do it seems to have ended up being a dbms job. I modified the docs a bit a long time ago, but unfortunately it looks like they still recommend ad-context-server, which we stopped using a while back in favor of a dbms job. I'm not sure if the problem was ever really "online", I think it was more that rebuilding the same thing twice at once used to cause problems.
Also, there was a bug in some versions of ACS 3.3 whereby multiple sites on the same box would overwrite each others jobs upon running the sws create script. Phong and Mike Bryzek fixed it somewhere around 3.4. Don't remember exact version #s.
End result? Syncing via dbms_job with online seems to work on Oracle 8.1.6.2, and it all seems to transparently quietly and happily work in ACS4 for the lucky people on Solaris boxes, and it seems to be possible to get going for people on Linux but I never learned the details (think you just have to comment out the INSO stuff since the filters aren't available on Linuxm, or replace their ctxhx conversion program with your own)
