Please upgrade. If you have problems with the latest version we can look into it more.
You can also look at command counters for odd commands being given: make sure nobody's running flushes, or "stats sizes", or "stats cachedump" since those can cause CPU spikes and hangs. With 1.4.20 you can use "stats conns" to see what the connections are doing during the cpu spike. On Thu, 7 Aug 2014, Claudio Santana wrote: > Forgot to say I'm running version 1.4.13 libevent 2.0.16-stable > > > > On Thu, Aug 7, 2014 at 6:08 PM, Claudio Santana <claudio.sant...@gmail.com> > wrote: > Sorry for the late response. > > My CPU utilization normally is min 2.5% to 6.5% max. > > So it's interesting you ask this. The reason why I submitted the 1st question > is because I've experienced some random CPU > utilization spikes. From this about 6% CPU utilization all of the sudden it > spikes to 100% and I can see the offending > process is one of the Memcached instances. Sadly this CPU spike is > accompanied by all requests timing out causing the > whole system to become unusable. > > I collect minute by minute stats of all these memcached instances and > according to my stats this issue happens within 2 > minutes. I can see in the number of commands there's no increase in number of > commands being issued right before the CPU > spike nor increase in the number of bytes in/out. > > Does anybody have any ideas of what could be going on? > > I have all Memcached stats collected by minute in Graphite, I can provide > other stats that could help explain this issue > if necessary. > > > On Mon, Aug 4, 2014 at 9:36 PM, dormando <dorma...@rydia.net> wrote: > You could run one instance with one thread and serve all of that just > fine. have you actually looked at graphs of the CPU usage of the host? > memcached should be practically idle with load that low. > > One with -t 6 or -t 8 would do it just fine. > > On Mon, 4 Aug 2014, Claudio Santana wrote: > > > Dormando, thanks for the quick response. Sorry for the confusion, I > don't have exact metrics per second but > per minute 1.12 > > million sets and 1.8 million gets which translates to 18,666 sets per > minute and 30,000 gets per second. > > > > These stats are per Memcached instance which I currently run 3 on > each server. > > > > Claudio. > > > > > > On Mon, Aug 4, 2014 at 6:22 PM, dormando <dorma...@rydia.net> wrote: > > On Mon, 4 Aug 2014, Claudio Santana wrote: > > > > > I have this Memcached cluster where 3 instances of Memcached > run in a single server. These servers > have 24 cores, > > each instance > > > is configured to have 8 threads each. Each individual > instance serves have about 5000G gets/sets a > day and about > > 3k current > > > connections. > > > > I don't know what "5000G gets/sets a day" translates to in per-second > (nor > > what the G-unit even is?), can you define this? > > > > > What would be better? consolidate these 3 instances to a single > instance per server with 24 threads? I've > read in a few > > articles > > > that Memcached's performance starts suffering with more than 4-6 > threads per instance, is this generally > true? > > > > > > How about keeping the 3 instances per server and decreasing the > number of threads to say 4 or 6? or > creating 4 instances > > in the > > > same servers instead of 3 and decreasing the number of threads per > instance to 6 so there is one thread > per core. > > > > > > Is there a guide you could recommend to configure the right number > of threads and strategies to get the > most out of a > > Memcached > > > server/instance? > > > > > > Thanks, > > > Claudio > > > > > > -- > > > > > > --- > > > You received this message because you are subscribed to the Google > Groups "memcached" group. > > > To unsubscribe from this group and stop receiving emails from it, > send an email to > > memcached+unsubscr...@googlegroups.com. > > > For more options, visit https://groups.google.com/d/optout. > > > > > > > > > > -- > > > > --- > > You received this message because you are subscribed to the Google > Groups "memcached" group. > > To unsubscribe from this group and stop receiving emails from it, > send an email to > memcached+unsubscr...@googlegroups.com. > > For more options, visit https://groups.google.com/d/optout. > > > > > > -- > > > > --- > > You received this message because you are subscribed to the Google > Groups "memcached" group. > > To unsubscribe from this group and stop receiving emails from it, > send an email to > memcached+unsubscr...@googlegroups.com. > > For more options, visit https://groups.google.com/d/optout. > > > > > > -- > > --- > You received this message because you are subscribed to the Google > Groups "memcached" group. > To unsubscribe from this group and stop receiving emails from it, send > an email to > memcached+unsubscr...@googlegroups.com. > For more options, visit https://groups.google.com/d/optout. > > > > -- > > --- > You received this message because you are subscribed to the Google Groups > "memcached" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to memcached+unsubscr...@googlegroups.com. > For more options, visit https://groups.google.com/d/optout. > > -- --- You received this message because you are subscribed to the Google Groups "memcached" group. 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