A lot of churn is hard on Cassandra because of
http://wiki.apache.org/cassandra/DistributedDeletes, but Cassandra is
so fast that it may make up for that depending on your needs.

It's not designed to eliminate i/o entirely, no.  But if you set
RowsCached=100% in 0.6 you'll get something pretty close to that.
(That is a better approach than huge Memtables.)

-Jonathan

On Thu, Mar 4, 2010 at 9:44 PM, Bill Au <bill.w.au@gmail.com> wrote:
> I am running on a machine with 16 GB of memory.  I am thinking that the
> bigger MemtableSizeIbMB, the more data will be kept in memory so there will
> be less disk I/O.  Can I eliminate disk I/O all together if all my data fits
> inside Memtable?  My application is constantly inserting new data and remove
> old ones.  Will keeping everything in Memtable generate so much garbage
> collection activity that it would impact performance?
> Bill
>
>