Dnia 2010-05-17, pon o godzinie 14:45 -0700, Chih Yin pisze: > Hi, > > > Please excuse me if the information contained in this email is a bit > generic. I'm not the regular administrator, but I've been given the > task of troubleshooting some issues with my website. If more details > are needed, I'll gladly go look for additional information. > > > Currently, my website is experiencing a lot of errors and slowness. > The server errors I see in the HAProxy log file are mainly 503 > errors. The slowness of page loads for my website can be as long as > minutes. I'm trying to determine if anyone have had any similar > issues with using HAProxy as a high availability load balancer. > > > HAProxy 1.3.21 > CentOS running on Citrix XenServer > HP blades > > > There are actually almost 100 virtual servers running on the > blades. A good many of the virtual servers are application servers > running Glassfish. There are a few servers dedicated to CAS for > authentication and access. I have three servers running Rsyslogd for > writing HAProxy log data to file. A NetApp filer is used for storage. > > > Currently, the website gets about: > > > 73,000 pageviews a day > 32,000 unique visitors a day > 46,000 visit a day > > > 3,000 pageviews a hr > 1,300 unique visitors a hr > 1,000 visit a hr > > > I am using Akamai to help manage content delivery. > > > One of the things Akamai is reporting to me is that they are having > difficulty requesting content that needs to be refreshed. Akamai > tries up to 4 times to get the content with a 2 second timeout to > update content whose TTL has expired. After the 4th time, Akamai > looks to their own cache before returning a 503 error to the user if > the content is not available in the cache. > > > Recently, I've noticed that Akamai is encountering an increasingly > large number of 503 and 404 errors from my website. I've traced the > 404 errors to missing images, but I'm not sure what the cause of the > 503 errors could be. I had some external resources help me verify > that they are able to retrieve the content from the Glassfish > application servers even when HAProxy is reporting the 503 errors. > > > One thing I did notice about the HAProxy configuration is that there > are actually three servers running HAProxy with identical > configurations. One serves as the primary high availability load > balancer while the other two act as failovers. The keep-alive daemons > are configured to accomodate that setup. > > > From this generic description, is there something in the way this > architecture is set up or in the configuration of HAProxy that may be > causing the 503 errors to be reported to Akamai? As I mentioned, when > an external resource makes a request for the same content directly > from the application server, the same errors do not appear to occur. >
503 would (usually) mean haproxy sees backends as DOWN, look for msg about server goin up/down in haproxy logs. Or, if thats not a case, grep haproxy logs for those 503 errors (make sure ure using http log mode), then go to section 8 in http://haproxy.1wt.eu/download/1.3/doc/configuration.txt and try to determine what was exact reason for error and/or post few examples here, your haproxy config (with "sensitive" information removed ofc ;) ) Having some kind of monitoring, or at least stats page active is also very helpful. -- Mariusz Gronczewski (XANi) <xani...@gmail.com> GnuPG: 0xEA8ACE64 http://devrandom.pl
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