yes, I would do raid1 on 2 commitlog disks and raid10 on the 6 remaining for OS + data
On Mon, May 24, 2010 at 2:27 PM, Aaron McCurry <amccu...@gmail.com> wrote: > 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 >> > > -- Jonathan Ellis Project Chair, Apache Cassandra co-founder of Riptano, the source for professional Cassandra support http://riptano.com
