> Minor compactions (see > http://wiki.apache.org/cassandra/MemtableSSTable) will try to keep the > growth in check but it is by no means limited to 2x.
Sorry I was being unclear. I was rather thinking along the lines of a doubling of data triggering an implicit major compaction. However I was wrong anyway, since minimumCompactionThreshold in CompactionManager is set to 4. This does make me realize that the actual worst-case spike of disk space usage is decidedly non-trivial to figure out, even if we are allowed to assume that compaction speed is equal to or greater than the speed of writes. -- / Peter Schuller