On Mon, Jun 21, 2010 at 12:24 PM, Peter Schuller < peter.schul...@infidyne.com> wrote:
> > Just an update here. We're now entirely on standard IO mode, and > everything > > is stable and happy. There hasn't been much of a performance hit, if at > all. > > Cool. Just be aware that if my speculation was correct that you're (1) > dedicating a very large portion of system memory to cassandra, but (2) > most of that is unused in the sense of being live, you are probably > going to see more disk I/O on reads than you would otherwise due to > less data fitting in cache (assuming your access pattern has some kind > of locality to make caching effective, and assuming you did not crank > up the in-JVM caching when switching to standard I/O mode). > Of course. We've got about 75% of available memory dedicated to Cassandra row caches which leaves just under 6GB for fs caches, which is just under 10% of the load on the machine. We're probably going to put a lot more memory in these nodes at this point. > > -- > / Peter Schuller >
