> However, when I run a repair my CMS usage graph no longer shows sudden drops > but rather gradual slopes and only manages to clear around 300MB each GC. > This seems to occur on 2 other nodes in my cluster around the same time, I > assume this is because they're the replicas (we use 3 replicas). Parnew > collections look about the same on my graphs with or without repair running > so no trouble there so far as I can tell.
I don't know why leveled/snappy would affect it, but disregarding that, I would have been suggesting that you are seeing additional heap usage because of long-running repairs retaining sstables and delaying their unload/removal (index sampling/bloom filters filling your heap). If it really only happens for leveled/snappy however, I don't know what that might be caused by. -- / Peter Schuller (@scode, http://worldmodscode.wordpress.com)
