have you benchmarked the difference between using the ram disk and turning off sync with forceSync=no? i would think that the performance will be similar. you will need to use the code in trunk because https://issues.apache.org/jira/browse/ZOOKEEPER-1087 isn't in any of the releases yet.
thanx ben On Thu, Sep 1, 2011 at 1:31 PM, Ashwin Jayaprakash <[email protected]> wrote: > This is a follow up to a question I posted in July 2010 - about whether the > recovery log could be redirected to /dev/null or some such low latency drive > [http://markmail.org/thread/3edpfmvn2fhyg5wv]. > > I just found out that Linux distros with 2.6 kernel have a built-in shared > memory file system that runs purely in memory - /dev/shm. Since this > provides recovery across JVM restarts (but not OS restarts) wouldn't this be > sufficient to run the ZK nodes off this drive? Replicas are on other > machines anyway so FT/HA is already there. It's just that disk latency can > be eliminated completely. > > [Apologies if you guys are already aware of /dev/shm] > > I ran some simple Java IO tests (not full ZK) on this drive and I wanted to > share my results. Might be of some use to apps that require low latency: > http://javaforu.blogspot.com/2011/09/ram-disk-is-already-in-linux-and-nobody.html > > Ashwin. >
