Somewhere in the AdminGuide there is the statement that the BA DB process will preempt all other processes. We have in the past presumed this to be true, tho we've never observed it in reality.
Out current hardware setup is the number of disk storage pools plus the DB is one greater than the number of tape drives available. This caused no problems in V3R7 of earlier releases (in V2 and V3R1, there were two less drives than disk pools), but since upgrading to V4R1 in January, we have experienced the system going down with the log full about once a week. Setting the log trigger to 40% has not remedied the situation: if all disk storage pools are in migration, the only other tape process I allow during the backup production window, the incremental DB dump seems to wait until a drive frees naturally, and with collocated tapepools, that can take longer that the logfile can hold out. The question is, did I miss something when installing the upgrade about setting priorities for processes? or was I just lucky that the system I inherited when we upgraded to V2R1 never was busy enough to trigger the situation? I should add that I process about 800-850 clients a night on each of my servers.