On Wed, Aug 24, 2011 at 1:54 PM, Jacob, Arun <[email protected]> wrote: > we need to cap data size at 50% of total node storage capacity for > compaction
Sort of. There's some fine print, such as the 50% number is only if you're manually forcing major compactions, which is not recommended, but a bigger thing to know is that 1.0 will introduce "leveled compaction" [1] inspired by leveldb. The free space requirement will then be a small number of megabytes. [1] https://issues.apache.org/jira/browse/CASSANDRA-1608 > SSDs are preferred, but of course reduce storage capacity > using standard storage means you bump up your RAM to keep as much in memory > as possible. You want to keep "as much in ram as possible" either way; whether you need SSDs or not depends on whether that's adequate for your "hot" working set. > is 8TB (meaning 1.33 actual TB storage/node) a reasonable per node storage > size for Cassandra? That's fine, but keep in mind that repairing that much data if you lose a node could take a while. Other things being equal, I'd prefer more nodes with less capacity. -- Jonathan Ellis Project Chair, Apache Cassandra co-founder of DataStax, the source for professional Cassandra support http://www.datastax.com
