Is 1.2 JBOB and april fools joke? Heh, seriously though, I have no idea what you are talking about there. I am trying to get raw disk performance with no cassandra involved before involving cassandra…..which is the next step.
Thanks, Dean From: aaron morton <aa...@thelastpickle.com<mailto:aa...@thelastpickle.com>> Reply-To: "user@cassandra.apache.org<mailto:user@cassandra.apache.org>" <user@cassandra.apache.org<mailto:user@cassandra.apache.org>> Date: Monday, April 1, 2013 11:01 PM To: "user@cassandra.apache.org<mailto:user@cassandra.apache.org>" <user@cassandra.apache.org<mailto:user@cassandra.apache.org>> Subject: Re: how to test our transfer speeds If not, maybe I just generate the same 1,000,000 files on each machine, then randomly delete 1/2 the files and stream them from the other machine as writing those files would all be in random locations again forcing a much worse measurement of MB/sec I would think. Not sure I understand the question. But you could just scrub the data off a node and rebuild it. Note that streaming is throttled, and it will also generate compaction. He has twenty 1T drives on each machine and I think he also tried with one 1T drive seeing the same performance which makes sense if writing sequentially Are you using the 1.2 JBOB configuration? Cheers ----------------- Aaron Morton Freelance Cassandra Consultant New Zealand @aaronmorton http://www.thelastpickle.com On 1/04/2013, at 11:01 PM, "Hiller, Dean" <dean.hil...@nrel.gov<mailto:dean.hil...@nrel.gov>> wrote: (we plan on running similar performance tests on cassandra but wanted to understand the raw foot print first)….. Someone in ops was doing a test transferring 1T of data from one node to another. I had a huge concern I emailed him that this could end up being a completely sequential write not testing random access speeds. He has twenty 1T drives on each machine and I think he also tried with one 1T drive seeing the same performance which makes sense if writing sequentially. Does anyone know of something that could generate a random access pattern such that we could time that? Right now, he was measuring 253MB / second from the time it took and the 1T of data. I would like to find the much worse case of course. If not, maybe I just generate the same 1,000,000 files on each machine, then randomly delete 1/2 the files and stream them from the other machine as writing those files would all be in random locations again forcing a much worse measurement of MB/sec I would think. Thoughts? Thanks, Dean
