Thanks, a lot! So for RAID 10, is the thought that the node can survive a single disk failure and keep going until a normal maintain cycle? Also are you saying that you would configure a single RAID 10 for the whole box? OS included? I have 8 x 500 Gig drives, so that would leave me with 2T per box, which I think is fine. But I do have one question, in this configuration would commit log writing and data directory compaction interfere with one another? Just based on what I read, it seems as though you want at least disks/partitions, one for commit log and one for data. Thanks again for the feedback!
Aaron On Mon, May 24, 2010 at 3:12 PM, Ian Soboroff <isobor...@gmail.com> wrote: > My data disks on two of my nodes are RAID-5, just because of > circumstances. My other nodes are JBOD. I don't notice any real > difference, but I haven't strongly benched it. > Ian > > > On Mon, May 24, 2010 at 2:45 PM, Jonathan Ellis <jbel...@gmail.com> wrote: > >> I can think of at least 2 clusters running 32GB boxes with single >> Cassandra processes on each. (16 seems to be more common.) At 64 I >> would seriously consider multiple processes per machine. You'd want >> to configure a Snitch such that same-machine boxes were considered the >> same rack, there is no separate closeness level of same machine. >> >> At 32 I think you're fine with one process. Watch for latency spikes >> and see how it goes. >> >> I would run raid 10 on the data disks if you can afford giving up the >> space, otherwise raid0. I don't know that anyone's tested raid5. >> >> On Sun, May 23, 2010 at 3:30 PM, Aaron McCurry <amccu...@gmail.com> >> wrote: >> > I am planning on setting up a Cassandra cluster on a small 16 node >> cluster >> > (possibly 32 way). Each machine has 8 cores 32 Gig of ram and 8 hds. >> My >> > first thought is to setup one of those hds for the commit log, 6 for >> data >> > and leave one for the OS. However I do have a concern about best >> utilizing >> > my memory, should I run a larger heap? Should I run several cassandra >> > processes on the same box? >> > My concern about the larger heap is because GC's typically get slower. >> And >> > if I run several procs, does cassandra realize that it's the same box >> for >> > replication purposes? >> > I do have other hd conf options, hardware RAID 0,1,or 5. >> > Just looking for some general configuration options as well as some real >> > world successes with similarly sized hardware. Thanks! >> > Aaron >> >> >> >> -- >> Jonathan Ellis >> Project Chair, Apache Cassandra >> co-founder of Riptano, the source for professional Cassandra support >> http://riptano.com >> > >
