Upgrades go pretty easy, with the OSgrid version everything is preconfigured and one only needs to copy the regions.ini file and edit 2 files if using mysql, 1 file if using the built-in sqlite.
I changed my server from openSUSE to Ubuntu as its much easier to use, but as before I've run into the same SIGABRT error/crash in one region, a little googling found its related to mono and that reinstalling mono etc etc doesn't fix the problem.
It was occasional on openSUSE, but now more frequent, and usually happened when there was nothing at all going on.
I also noticed my processor use would spike to 100% or more and stay there, and the memory use would go to 6 gb out of the 7.8 gb available and it would crash the one region/instance and display an error about not enough memory available to analize the error and send it to the developers.
So I googled again and found references and a mantis about the warp3D map tile module reported as causing the memory and processor spike, so I commented out the warp3D map tiles line, restarted and since I did that yesterday I haven't see the problem.
with 9 regions and 3 instances of OS/mysql running and my avatar logged in, the monitor shows CPU use is around 10%, memory use is around 1.0gb (14%) and holding steady.
While upgrading to 1.7.5 and Ubuntu, I ran into two familiar errors I could never remember how I fixed them, one was: [Region name] is not part of an estate, the other was something about an "object is not set to an instance of an object" or some such clueless message that is meaningless, I believe the cause of both is because my mysql connection string's database name was wrong and didn't match, it was opensim3 and it should have been opensim, once I changed that connection string to the correct database it started up normally.