It would be helpful if you described the physical characteristics of the servers: memory size, logical cpu count, etc.
Google created leveldb to be highly reliable in the face of crashes. If it is not restarting, that suggests to me that you have a low memory condition that is not able to load leveldb's MANIFEST file. That is easily fixed by moving the dataset to a machine with larger memory. There is also a special flag to reduce Riak's leveldb memory foot print during development work. The setting reduces the leveldb performance, but lets you run with less memory. In riak.conf, set: leveldb.limited_developer_mem = true Matthew > On Jul 12, 2016, at 11:56 AM, Vikram Lalit <vikramla...@gmail.com> wrote: > > Hi - I've been testing a Riak cluster (of 3 nodes) with an ejabberd messaging > cluster in front of it that writes data to the Riak nodes. Whilst load > testing the platform (by creating 0.5 million ejabberd users via Tsung), I > found that the Riak nodes suddenly crashed. My question is how do we recover > from such a situation if it were to occur in production? > > To provide further context / details, the leveldb log files storing the data > suddenly became too huge, thus making the AWS Riak instances not able to load > them in memory anymore. So we get a core dump if 'riak start' is fired on > those instances. I had an n_val = 2, and all 3 nodes went down almost > simultaneously, so in such a scenario, we cannot even rely on a 2nd copy of > the data. One way to of course prevent it in the first place would be to use > auto-scaling, but I'm wondering is there a ex post facto / post the event > recovery that can be performed in such a scenario? Is it possible to simply > copy the leveldb data to a larger memory instance, or to curtail the data > further to allow loading in the same instance? > > Appreciate if you can provide inputs - a tad concerned as to how we could > recover from such a situation if it were to happen in production (apart from > leveraging auto-scaling as a preventive measure). > > Thanks! > > _______________________________________________ > riak-users mailing list > riak-users@lists.basho.com > http://lists.basho.com/mailman/listinfo/riak-users_lists.basho.com _______________________________________________ riak-users mailing list riak-users@lists.basho.com http://lists.basho.com/mailman/listinfo/riak-users_lists.basho.com
