Greetings. I tried running Riak with bitcask backend on 7 Amazon EC2 standard large instances (7.5 GB RAM, 4 EC2 CPU units) and performed some tests. For comparison, I built up the following Riak clusters:
7 physical nodes ring 1 physical node ring (on one of the 7 instances, but I ran the tests separately so the rings won't mess with each other) 1 physical node ring on an extra large instance (15 GB RAM, 8EC2 CPU units) and ran a couple of tests with putting and getting data using Riak native Erlang API (not PBC). I had 2 buckets, the first one having small (averagely about 1KB) values, but a lot of them (about several millions) called "entities", and the second one having lists of keys from the first database, called "documents". So, every document consists of a lot of entities (I used 100 and 1000 for my tests). So, the approximate size of every document was either 100KB or 1MB. So, I performed tests of putting documents and entities to database and then obtaining them. I tried to perform reads and writes using 10 and 100 concurrent Erlang processes (well, 100 was generally too much as I ran out of CPU), first from only one machine and then from 2 and 3 machines at the same time (for the 7-nodes ring). Of course, the entities were obtained using map-reduce. The first weird thing was that even with 10 concurrent reads and writes the performance didn't differ for all three clusters. Okay, 1 large and 1 extra large nodes don't differ so much but the 7 nodes should have given me some performance, shouldn't they? The second thing was that the average read time for one document with 1000 entities was about 5 seconds, and again, the number of machines in the cluster didn't affect the result. I guess I just stumbled upon the performance of the instance that sent all the map-reduce requests and then collected the replies because when I ran tests on the other 2 instances, all three had the same performance. The other strange thing was that during data writes most of the time nodes were not io-loaded. If it was a one-stream write, it would be obvious. But it were 10 and then 20 and 30 simultaneous writing processes! Unfortunately I cannot provide the detailed results now, they are pretty messed up. I'm going to use basho_bench to make good graphs and tables of these tests. Any advises for the future tests or any explanations for such strange performance? Thank you in advance and sorry for a little messed up e-mail. -- Best regards, Dmitry Demeshchuk _______________________________________________ riak-users mailing list [email protected] http://lists.basho.com/mailman/listinfo/riak-users_lists.basho.com
