before_fork should work fine. The children which will actually handle the requests will inherit everything from the parent, including any libraries that were loaded by the master process as a result of handling the mock requests. It'll also conserve memory, which is a nice benefit.
On Wed, Mar 4, 2015 at 12:24 PM, Sarkis Varozian <[email protected]> wrote: > That does make sense - I was looking at another suggestion from a user > here (Braulio) of running a "warmup" using rack MockRequest: > https://gist.github.com/brauliobo/11298486#file-unicorn-conf-rb-L77 > > The only issue I am having with the above solution is it is happening in > the before_fork block - shouldn't I warmup the connection in after_fork? If > I follow the above gist properly it warms up the server with the old > activerecord base connection and then its turned off, then turned back on > in after_fork. I think I am not understanding the sequence of events > there... If this is the case, I should warmup and also check/kill the old > master in the after_fork block after the new db, redis, neo4j connections > are all created. Thoughts? > > On Wed, Mar 4, 2015 at 12:17 PM, Michael Fischer <[email protected]> > wrote: > >> I'm not exactly sure how preload_app works, but I suspect your app is >> lazy-loading a number of Ruby libraries while handling the first few >> requests that weren't automatically loaded during the preload process. >> >> Eric, your thoughts? >> >> --Michael >> >> On Wed, Mar 4, 2015 at 11:58 AM, Sarkis Varozian <[email protected]> >> wrote: >> >>> Yes, preload_app is set to true, I have not made any changes to the >>> unicorn.rb from OP: http://goo.gl/qZ5NLn >>> >>> Hmmmm, you may be onto something - Here is the i/o metrics from the >>> server with the highest response times: http://goo.gl/0HyUYt (in this >>> graph: http://goo.gl/x7KcKq) >>> >>> Looks like it may be i/o related as you suspect - is there much I can do >>> to alleviate that? >>> >>> On Wed, Mar 4, 2015 at 11:51 AM, Michael Fischer <[email protected]> >>> wrote: >>> >>>> What does your I/O latency look like during this interval? (iostat -xk >>>> 10, look at the busy %). I'm willing to bet the request queueing is >>>> strongly correlated with I/O load. >>>> >>>> Also is preload_app set to true? This should help. >>>> >>>> --Michael >>>> >>>> On Wed, Mar 4, 2015 at 11:48 AM, Sarkis Varozian <[email protected]> >>>> wrote: >>>> >>>>> Michael, >>>>> >>>>> Thanks for this - I have since changed the way we are restarting the >>>>> unicorn servers after a deploy by changing capistrano task to do: >>>>> >>>>> in :sequence, wait: 30 >>>>> >>>>> We have 4 backends and the above will restart them sequentially, >>>>> waiting 30s (which I think should be more than enough time), however, I >>>>> still get the following latency spikes after a deploy: >>>>> http://goo.gl/tYnLUJ >>>>> >>>>> This is what the individual servers look like for the same time >>>>> interval: http://goo.gl/x7KcKq >>>>> >>>>> >>>>> >>>>> On Tue, Mar 3, 2015 at 2:32 PM, Michael Fischer <[email protected]> >>>>> wrote: >>>>> >>>>>> If the response times are falling a minute or so after the reload, >>>>>> I'd chalk it up to a cold CPU cache. You will probably want to stagger >>>>>> your reloads across backends to minimize the impact. >>>>>> >>>>>> --Michael >>>>>> >>>>>> On Tue, Mar 3, 2015 at 2:24 PM, Sarkis Varozian <[email protected]> >>>>>> wrote: >>>>>> >>>>>>> We have a rails application with the following unicorn.rb: >>>>>>> http://goo.gl/qZ5NLn >>>>>>> >>>>>>> When we deploy to the application, a USR2 signal is sent to the >>>>>>> unicorn >>>>>>> master which spins up a new master and we use the before_fork in the >>>>>>> unicorn.rb config above to send signals to the old master as the new >>>>>>> workers come online. >>>>>>> >>>>>>> I've been trying to debug a weird issue that manifests as "Request >>>>>>> Queueing" in our Newrelic APM. The graph shows what happens after a >>>>>>> deployment (represented by the vertical lines). Here is the graph: >>>>>>> http://goo.gl/iFZPMv . As you see from the graph, it is >>>>>>> inconsistent - >>>>>>> there is always a latency spike - however, at times Request Queueing >>>>>>> is >>>>>>> higher than previous deploys. >>>>>>> >>>>>>> Any ideas on what exactly is going on here? Any suggestions on >>>>>>> tools/profilers to use to get to the bottom of this? Should we >>>>>>> expect this >>>>>>> to happen on each deploy? >>>>>>> >>>>>>> Thanks, >>>>>>> >>>>>>> -- >>>>>>> *Sarkis Varozian* >>>>>>> [email protected] >>>>>>> >>>>>>> >>>>>>> >>>>>> >>>>> >>>>> >>>>> -- >>>>> *Sarkis Varozian* >>>>> [email protected] >>>>> >>>> >>>> >>> >>> >>> -- >>> *Sarkis Varozian* >>> [email protected] >>> >> >> > > > -- > *Sarkis Varozian* > [email protected] >
