Here is what I do when the recovery log fills, also on AIX. My notes agree
with the person who said that the Extend size has to be a multiple of 4
and 1 less than the DSMFMT size. (What the other person said about max
size being 5G, might cause this to not work, though.)

If server will not start because the recovery log is full:
  1) Find a location for an extra recovery log file
  2) DSMFMT -LOG <fullfn> <size1> -- where size1 = 4x+1, where x => 2
  3) DSMSERV EXTEND LOG <fullfn> <size2> -- where size2 = size1-1
  4) DSMSERV -- to start the server normally
  5) Solve the problem that caused the recovery log to fill.
  6) After the server is up, either create a mirror for this recovery log
or preferably remove it from use.

Nancy Reeves
Technical Support, Wichita State University
Nancy.Reeves AT wichita DOT edu          316-978-3860