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The "LargeDataSetConsiderations" page has been changed by PeterSchuller. http://wiki.apache.org/cassandra/LargeDataSetConsiderations?action=diff&rev1=14&rev2=15 -------------------------------------------------- * Repair operations can increase disk space demands (particularly in 0.6, less so in 0.7; TODO: provide actual maximum growth and what it depends on). * As your data set becomes larger and larger (assuming significantly larger than memory), you become more and more dependent on caching to elide I/O operations. As you plan and test your capacity, keep in mind that: * The cassandra row cache is in the JVM heap and unaffected (remains warm) by compactions and repair operations. This is a plus, but the down-side is that the row cache is not very memory efficient compared to the operating system page cache. - * The key cache is affected by compaction and repair. + * The key cache is affected by compaction because it is per-sstable, and compaction moves data to new sstables. * Soon no longer true as of: [[https://issues.apache.org/jira/browse/CASSANDRA-1878|CASSANDRA-1878]] * The operating system's page cache is affected by compaction and repair operations. If you are relying on the page cache to keep the active set in memory, you may see significant degradation on performance as a result of compaction and repair operations. * Potential future improvements: [[https://issues.apache.org/jira/browse/CASSANDRA-1470|CASSANDRA-1470]], [[https://issues.apache.org/jira/browse/CASSANDRA-1882|CASSANDRA-1882]].
