Having the both the commit log and data directory on the same volume is generally not recommended. You would actually see a performance decrease unless you can have most your reads be cache hits.
On Friday, August 10, 2012, Thibaut Britz wrote: > Hi, > > Has anyone of you made some experience with software raid (raid 1, > mirroring 2 disks)? > > Our workload is rather read based at the moment (Commit Log directory only > grows by 128MB every 2-3 minutes), while the second hd is under high load > due to the read requests to our cassandra cluster. > > I was thinking about putting both the commit log and the data directory on > a software raid partition spanning over the two disks. Would this increase > the general read performance? In theory I could get twice the read > performance, but I don't know how the commit log will influence the read > performance on both disks? > > Thanks, > Thibaut > >
