You cannot start level compaction. It will run based on data in each level. 

On Thu, Sep 19, 2013 at 9:19 AM, Nate McCall <> wrote:
As opposed to stopping compaction altogether, have you experimented with turning down compaction_throughput_mb_per_sec (16mb default) and/or explicitly setting concurrent_compactors (defaults to the number of cores, iirc). 

On Thu, Sep 19, 2013 at 10:58 AM, rash aroskar <> wrote:
In general leveled compaction are I/O heavy so when there are bunch of writes do we need to stop leveled compactions at all?
I found the nodetool stop COMPACTION, which states it stops compaction happening, does this work for any type of compaction? Also it states in documents 'eventually cassandra restarts the compaction', isn't there a way to control when to start the compaction again manually ? 
If this is not applicable for leveled compactions in 1.2, then what can be used for stopping/restating those?