Hi Sergey,<div><br></div><div>We (OpenX) have a riak_core based application that's running on a 125 node cluster (there are also other smaller clusters). We never really tested to see where it would fall over (and the cluster was much smaller when it started), but I see no indicators that it will fall over when we add the 126th node. FWIW, it's running riak_core 0.13.0, and I assume the newer versions of riak_core have only gotten better. Answers to some of your other questions (based solely on my experience) in-line below.<br>
<br><div class="gmail_quote">On Fri, Sep 21, 2012 at 6:29 AM, Zhemzhitsky Sergey <span dir="ltr"><<a href="mailto:Sergey_Zhemzhitsky@troika.ru" target="_blank">Sergey_Zhemzhitsky@troika.ru</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
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<p class="MsoNormal"><span lang="EN-US">Hello gurus,<u></u><u></u></span></p>
<p class="MsoNormal"><span lang="EN-US"><u></u> <u></u></span></p>
<p class="MsoNormal"><span lang="EN-US">We’re developing a riak-core application, that does not include any persistence and works in-memory, and are wondering what are the best use cases to test riak-core and erlang itself in large-scale deployments (>100 physical
nodes).<u></u><u></u></span></p>
<p class="MsoNormal"><span lang="EN-US"><u></u> <u></u></span></p>
<p class="MsoNormal"><span lang="EN-US">For example some of the map-reduce frameworks (like hadoop) have performance tests like terasort, etc., which can show to what extent the whole framework can be scaled.
<u></u><u></u></span></p>
<p class="MsoNormal"><span lang="EN-US"><u></u> <u></u></span></p>
<p class="MsoNormal"><span lang="EN-US">So could you share some ideas what are the best practices to test large-scale deployments of riak-core and erlang applications? What synthetic tests and benchmarks can be executed to answer the following questions:
<u></u><u></u></span></p>
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<p><u></u><span lang="EN-US"><span>1.<span style="font:7.0pt "Times New Roman"">
</span></span></span><u></u><span lang="EN-US">Does the system scale well?</span></p></div></div></blockquote><div>Yes, so far it has scaled well.</div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div lang="RU" link="blue" vlink="purple"><div><p><span lang="EN-US"> <u></u>
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<p><u></u><span lang="EN-US"><span>2.<span style="font:7.0pt "Times New Roman"">
</span></span></span><u></u><span lang="EN-US">Can the system be considered as linearly scalable?</span></p></div></div></blockquote><div>Yes, the riak_core portion can be considered linearly scalable. The overall behavior is largely dependent on what you're doing in your vnodes and how well you hash the things you want distributed. In theory, if you hash poorly you can get hot-spots that will prevent linear scalability, but I haven't seen that happen with our workload.</div>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div lang="RU" link="blue" vlink="purple"><div><p><span lang="EN-US"><u></u><u></u></span></p>
<p><u></u><span lang="EN-US"><span>3.<span style="font:7.0pt "Times New Roman"">
</span></span></span><u></u><span lang="EN-US">Is the system truly fault-tolerant?</span></p></div></div></blockquote><div>For the most part, 'yes', but that again depends on how you implement your vnode. The problems that I've encountered were due to my own inexperience with erlang when implementing my vnode.</div>
<div><br></div><div>In general I've been very happy with riak_core and we're definitely looking at using it more for places where it's the right solution.</div><div><br></div><div>Cheers,</div><div>Joel</div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div lang="RU" link="blue" vlink="purple"><div><p><span lang="EN-US"><u></u><u></u></span></p>
<p class="MsoNormal" style="text-autospace:none"><span lang="EN-US" style><u></u> <u></u></span></p>
<p class="MsoNormal" style="text-autospace:none"><span lang="EN-US" style>Best Regards,<u></u><u></u></span></p>
<p class="MsoNormal" style="text-autospace:none"><span lang="EN-US" style>Sergey
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