From: Sarkis Varozian <email@example.com> To: Michael Fischer <firstname.lastname@example.org> Cc: unicorn-public <email@example.com> Subject: Re: Request Queueing after deploy + USR2 restart Date: Wed, 4 Mar 2015 11:58:14 -0800 [thread overview] Message-ID: <CAGchx-JsOJD2m1ubTJEOeuK2EgP+NuyT=rD+--LPg6+vPnit8Q@mail.gmail.com> (raw) In-Reply-To: <CABHxtY5XU_cyda8JzZYJZCYB3GNfusS7z4jSP9k6V15AKNutFg@mail.gmail.com> 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 <firstname.lastname@example.org> 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@example.com> > 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 <firstname.lastname@example.org> >> 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@example.com> >>> 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* >>>> firstname.lastname@example.org >>>> >>>> >>>> >>> >> >> >> -- >> *Sarkis Varozian* >> email@example.com >> > > -- *Sarkis Varozian* firstname.lastname@example.org
next prev parent reply other threads:[~2015-03-04 19:58 UTC|newest] Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top 2015-03-03 22:24 Sarkis Varozian 2015-03-03 22:32 ` Michael Fischer 2015-03-04 19:48 ` Sarkis Varozian 2015-03-04 19:51 ` Michael Fischer 2015-03-04 19:58 ` Sarkis Varozian [this message] 2015-03-04 20:17 ` Michael Fischer 2015-03-04 20:24 ` Sarkis Varozian 2015-03-04 20:27 ` Michael Fischer 2015-03-04 20:35 ` Eric Wong 2015-03-04 20:40 ` Sarkis Varozian 2015-03-05 17:07 ` Sarkis Varozian 2015-03-05 17:13 ` Bráulio Bhavamitra 2015-03-05 17:28 ` Sarkis Varozian 2015-03-05 17:31 ` Bráulio Bhavamitra 2015-03-05 17:32 ` Bráulio Bhavamitra 2015-03-05 21:12 ` Eric Wong 2015-03-03 22:47 ` Bráulio Bhavamitra 2015-03-04 19:50 ` Sarkis Varozian [not found] ` <CAJri6_vidE15Xor4THzQB3uxyqPdApxHoyWp47NAG8m8TQuw0Q@mail.gmail.com> 2015-09-13 15:12 ` Bráulio Bhavamitra 2015-09-14 2:14 ` Eric Wong
Reply instructions: You may reply publicly to this message via plain-text email using any one of the following methods: * Save the following mbox file, import it into your mail client, and reply-to-all from there: mbox Avoid top-posting and favor interleaved quoting: https://en.wikipedia.org/wiki/Posting_style#Interleaved_style List information: https://yhbt.net/unicorn/ * Reply using the --to, --cc, and --in-reply-to switches of git-send-email(1): git send-email \ --in-reply-to='CAGchx-JsOJD2m1ubTJEOeuK2EgP+NuyT=rD+--LPg6+vPnit8Q@mail.gmail.com' \ --email@example.com \ --firstname.lastname@example.org \ --email@example.com \ --subject='Re: Request Queueing after deploy + USR2 restart' \ /path/to/YOUR_REPLY https://kernel.org/pub/software/scm/git/docs/git-send-email.html * If your mail client supports setting the In-Reply-To header via mailto: links, try the mailto: link
Code repositories for project(s) associated with this inbox: ../../unicorn.git This is a public inbox, see mirroring instructions for how to clone and mirror all data and code used for this inbox; as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).