Thanks Mohit and Michael,
That's what I thought. I have tried all the avenues, will give ParNew a try. With the 1.0.xx I have issues when data sizes go up, hopefully that will not be the case with 1.2.

Just curious, has anyone tried 1.2 with large data set, around 1 TB ?

Thanks !

On Thu, Oct 3, 2013 at 7:20 AM, MichaƂ Michalski <> wrote:
I was experimenting with 128 vs. 512 some time ago and I was unable to see any difference in terms of performance. I'd probably check 1024 too, but we migrated to 1.2 and heap space was not an issue anymore.


W dniu 02.10.2013 16:32, srmore pisze:

I changed my index_interval from 128 to index_interval: 128 to 512, does it
make sense to increase more than this ?

On Wed, Oct 2, 2013 at 9:30 AM, cem <> wrote:

Have a look to index_interval.


On Wed, Oct 2, 2013 at 2:25 PM, srmore <> wrote:

The version of Cassandra I am using is 1.0.11, we are migrating to 1.2.X
though. We had tuned bloom filters (0.1) and AFAIK making it lower than
this won't matter.

Thanks !

On Tue, Oct 1, 2013 at 11:54 PM, Mohit Anchlia <>wrote:

Which Cassandra version are you on? Essentially heap size is function of
number of keys/metadata. In Cassandra 1.2 lot of the metadata like bloom
filters were moved off heap.

On Tue, Oct 1, 2013 at 9:34 PM, srmore <> wrote:

Does anyone know what would roughly be the heap size for cassandra with
1TB of data ? We started with about 200 G and now on one of the nodes we
are already on 1 TB. We were using 8G of heap and that served us well up
until we reached 700 G where we started seeing failures and nodes flipping.

With 1 TB of data the node refuses to come back due to lack of memory.
needless to say repairs and compactions takes a lot of time. We upped the
heap from 8 G to 12 G and suddenly everything started moving rapidly i.e.
the repair tasks and the compaction tasks. But soon (in about 9-10 hrs) we
started seeing the same symptoms as we were seeing with 8 G.

So my question is how do I determine what is the optimal size of heap
for data around 1 TB ?

Following are some of my JVM settings


Thanks !