The most obvious thing I can see is that perhaps all your instances are on the same piece of intel hardware. Is that something you can verify? Perhaps you can stagger the request for instances, so that on a different day your request is provisioned onto a different piece of kit...
On Sat, Jan 11, 2014 at 6:03 AM, Andrew Hume <and...@research.att.com>wrote: > we (i and a colleague) have a system where we probe a large number of > IP addresses out there in the Internet. A probe consists of opening > a http URL on that system and when we get back the (expected) 401 > response, we close the connection. about 7% of the time, we get no response > and we close the connection after several seconds. > > for more or less any Intel-style server, we can run about 500-1000 > probes per second (via a driver program with 50-100 threads). > > here’s the unexpected part: we go to a cloud vendor and run this program > in a few instances, but no matter how many instances we run, once we get > to about 1000 probes/s total, additional instances or driving rates do not > increase the total rate, but simply increase packet loss and the number of > calls > from the cloud vendor. > > we’ve tried this on SIlverLining (an AT&T cloud) and RackSpace, with > pretty much identical results. we’ve hypothesized this as a limit of a > site-wide > NAT box or some such, but it seems unlikely. before we go repeat this > experiment > with other cloud vendors, does anyone have any comments on what this might > be > or if other vendors might do better or worse? > > andrew > > ----------------------- > Andrew Hume > 949-707-1964 (VO and best) > 732-420-0907 (NJ) > and...@research.att.com > > > > > _______________________________________________ > Tech mailing list > Tech@lists.lopsa.org > https://lists.lopsa.org/cgi-bin/mailman/listinfo/tech > This list provided by the League of Professional System Administrators > http://lopsa.org/ > >
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