Wouldn't I want flush_largest_memtables_at larger than my
OccupyingFraction? I want GC to kick in before I have to dump my memtables
not after.
On Wed, Apr 23, 2014 at 10:12 AM, Ruchir Jha wrote:
> Lowering CMSInitiatingOccupancyFraction to less than 0.75 will lead to
> more GC interference an
Lowering CMSInitiatingOccupancyFraction to less than 0.75 will lead to
more GC interference and will impact write performance. If you're not
sensitive to this impact, your expectation is correct, however make
sure your flush_largest_memtables_at is always set to less than or
equal to the occupancy
I'm in the process of trying to tune the GC and I'm far from an expert in
this area, so hoping someone can tell me I'm either out in left field or
on-track.
Cassandra's default GC settings are (abbreviated):
+UseConcMarkSweepGC
+CMSInitiaitingOccupancyFraction=75
+UseCMSInitiatingOccupancyOnly
Al
