I certainly won't get drawn into a public debate about which database is faster per node, but I would recommend you never take such claims at face value.
Eric On Apr 10, 2013, at 3:02 PM, Tom Zeng <[email protected]> wrote: > Thanks Eric for the info, that's very helpful. 7 was mentioned at the last > Riak DC meetup. not as the minimal but for better performance, when I was > chatting with a couple of Basho devs about performance benchmarking, and > about Riak is quite a bit slower on single node against Mongo. > > > On Wed, Apr 10, 2013 at 5:56 PM, Eric Redmond <[email protected]> wrote: > > > On Apr 10, 2013, at 2:26 PM, Tom Zeng <[email protected]> wrote: > >> Hi list, >> >> We have a production installation with only 3 nodes and running on 1.2.1. >> I'd appreciate to get some facts to convince IT to increase the number of >> nodes to 7 and upgrade to 1.3. I heard people from Basho mentioned ideally >> 7 nodes for production a couple of time, can someone explain why 7, is 4, or >> 5 nodes good enough? > > I'm not sure where you heard the number 7 as a minimum, unless if was for a > specific use-case. In general the minimum recommended number is 5 nodes. > > Running with only 3 nodes isn't a great idea. Since a core purpose of Riak is > to remain available in the face of outages, 3 will not support any outage. > Less than 3 is lower than the default replication value (N=3). This is so > important, in fact, that we recommend 5 solely to act as a buffer in the case > where 1 of the 5 is down, the remaining 4 is dangerously close to the > inflexible 3 node number. Even if you do not upgrade to 1.3, you really need > to have at least 5 nodes. > > There are many benefits to upgrading to 1.3, but one of the most compelling > from an operations point of view is active anti-entropy (AAE). Rather than > waiting on read-repair to fix inconsistent values (which is passive), AAE > routinely attempts to keep all node values in sync. This can be a godsend if > a node goes down, since you don't need to fore read-repair when you bring the > node back up by reading every key... you just let your cluster actively > self-heal. > > >> Also on the 3 three nodes, the file size for the bitcask directory very >> quite a bit: 21GB, 14GB, and 20GB. Could the node with only 14GB missing >> something or it's expected to have such big difference? > > There are several reasons sizes could be different. Values are not yet/ever > replicated (based on your N and W values). Files may have not been compacted. > Some keys have been deleted but not yet reaped... > >> Thanks, >> Tom >> >> -- >> Tom Zeng >> Director of Engineering >> Intridea, Inc. | www.intridea.com >> [email protected] >> (o) 888.968.4332 x519 >> (c) 240-643-8728 >> _______________________________________________ >> riak-users mailing list >> [email protected] >> http://lists.basho.com/mailman/listinfo/riak-users_lists.basho.com
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