> We only increased commitlog_total_space_in_mb so that Cassandra fully uses > the dedicated disk, but that may be an error? > The default value for this setting is (per the documentation): > > The default value is the smaller of 8192, and 1/4 of the total space of > the commitlog volume. > > But that doesn't say much (or should it really by 25% of the disk space?)
I wouldnt fill any filesystem intentionally that close to its partition size. Most (all?) will start to degrade performance-wise. Unless you are really strapped for disk space, give it some breathing room. This is best chosen by monitoring commitlog rotation frequency in conjunction with disk utilization for your cluster. > > So, my questions would be: > > * What size should I dedicate to this commit log disk? What are the rules of > thumb to discover the "best" size? > * How should I configure the "commitlog_total_space_in_mb" setting > respectively to the size of the disk? Most clusters shouldnt need to adjust this or any of the default commitlog settings unless you have excessively large mutations or require the commitlog getting written to disk more frequently. --------------------------------------------------------------------- To unsubscribe, e-mail: user-unsubscr...@cassandra.apache.org For additional commands, e-mail: user-h...@cassandra.apache.org
