There are a lot of things that go into this, but I would tend to suggest in a hosted VM senario, upping the ram is likely the right solution.
You mention thrashing, but what is that thrashing coming from? I assume all the boxes are thrashing and not just one or two of them? Is it due to swapping or is it just the raw disk access? Maybe you logging too aggressively? Perhaps your are suffering from a bad neighbor effect. If this is the case, increasing the amount of ram will likely put you on a physical host with few customers and thus you would be less likely to have a bad neighbor. Cost-wise in the VM world, you might be better off adding a few nodes rather than increasing the ram in your existing vm's. But then we are talking VMs and thus it should be fairly painless to experiment. I would try adding ram first and if that doesn't work, add a few nodes. Someone else my have a different opinion, but that is my two cents. On Wed, Dec 5, 2012 at 4:33 PM, Ken Perkins <[email protected]> wrote: > Hello all, > > We're seeing enough thrashing and low-memory on our production ring that > we've decided to upgrade our hardware. The real question is should we scale > up or out. > > Currently our ring is 512 partitions. We know that it's a sub-optimal size > but we can't easily solve that now. We're currently running a search-heavy > app on 5 8GB VMs. I'm debating between moving the VMs up to 16GB, or adding > a few more 8GB VMs. > > Some of the talk in #riak has pushed me towards adding more machines (thus > lowering the per node number of partitions) but I wanted to do a quick > sanity check here with folks that it's better than scaling up my current > machines. > > Thanks! > Ken Perkins > clipboard.com > > _______________________________________________ > riak-users mailing list > [email protected] > http://lists.basho.com/mailman/listinfo/riak-users_lists.basho.com > >
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