I was recently at a clients to look into a weird memory problem as they showed me something really strange.
The R5.0.11 server seems to be leaking memory. the nserver, nupdate and nhttp tasks were slowly creaping up in terms of memory usage. The nupdate task alone was using up about 350 Mb of RAM. I suspected a corrupt view index or something and did a compact to drop the indexes but afterwards the update task crept back up to about 350 Mb.
So where is the weirdness of this??? Well the guys who look after the server noticed that if they minimise the domino console screen the memory usage for the tasks dropped back down to about 3 Mb Ram. Then it would slowly start climbing again and then they just do a restore of the screen and the figure drops back to 3 Mb Ram.