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 <[email protected]> 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 <[email protected]> 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 > > [email protected]. > > > 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 [email protected]. > > 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 [email protected]. > > 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 [email protected]. > 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 [email protected]. For more options, visit https://groups.google.com/d/optout.
