Or, \u00ab\u00a0What I’ve learned about Graphite configuration\u00a0\u00bb.<\/p>\n
Last week, I worked on configuring Graphite and had to understand how it stores and aggregates data. So here are a few facts.<\/p>\n
The way our data will be stored is described in \/opt\/graphite\/conf\/storage-schemas.conf<\/em>. As an example:<\/p>\n This worked great when I was looking at data from the last 30 minutes. This behaviour comes from the file \/opt\/graphite\/conf\/storage-aggregation.conf<\/em> where we find the following lines:<\/p>\n Our problem comes from xFilesFactor<\/em>. It means that by default, we need at least 50% of the data to be non-null to store an average value. Think about it.<\/p>\n So here, I’m having a metric every second during 30 minutes. If Graphite doesn’t have something for a given second, the value is set to null. Fine, let’s move forward. In our case, Graphite tries to average one minute of data (1m:1d) with the precision of 1s from the first retention rule (1s:30m). To understand why nothing is displayed, consider I’m Collectd is sending data to Graphite. On average, metrics are arriving every 3s. On a one minute interval, we gather 20 values but Graphite is considering 60 values, 40 being null. We only have 33% (0.33) metrics usable which is lower than 50% Graphite is waiting for so the averaged value is set to null.<\/p>\n Now that we updated our configuration, set xFilesFactor<\/em> to 0 to be sure, restart carbon-cache, everything should work fine…<\/p>\n But that’s not the case; no change.<\/p>\n In fact, previous configuration is still being used in wsp storage files. We can check it with whisper-info.py<\/em>.<\/p>\n See, we still have xFilesFactor<\/em>: 0.5. The other solution consists in using whisper-resize.py<\/em> to enforce the new configuration. The above works fine, but this is the other way to configure how many metrics Graphite can keep. It has the format n:i<\/em>, which means we store a measure every n<\/em> seconds and we want i<\/em> points to be stored (computed with interval \/ n).<\/p>\n \nExample:<\/span> 3s:30m<\/em> 3:600<\/p>\n So 3s:30m,1m:1d,5m:2y gives us 3:600 60:1440 300:210380.<\/p>\n \u00ab\u00a0An average Gregorian year is 365.2425 days = 52.1775 weeks = 8765.82 hours = 525949.2 minutes = 31556952 seconds (mean solar, not SI).\u00a0\u00bb Wikipedia<\/p>\n<\/blockquote>\n Thing to remember concerning storage-schemas.conf (taken from Graphite doc<\/a>):<\/p>\n \u00ab\u00a0Changing this file will not affect already-created .wsp files. Use whisper-resize.py to change those.\u00a0\u00bb<\/p><\/blockquote>\n","protected":false},"excerpt":{"rendered":" Or, \u00ab\u00a0What I’ve learned about Graphite configuration\u00a0\u00bb. Last week, I worked on configuring Graphite and had to understand how it stores and aggregates data. So here are a few facts. Graphite Retention The way our data will be stored is described in \/opt\/graphite\/conf\/storage-schemas.conf. As an example: [default] pattern = .* retentions = 1s:30m,1m:1d,5m:2y This worked … Continuer la lecture de « Magical Graphite »<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[126],"tags":[187,92,188,184,189],"class_list":["post-1622","post","type-post","status-publish","format-standard","hentry","category-logiciellibre","tag-aggregation","tag-configuration","tag-graph","tag-graphite","tag-xfilesfactor"],"_links":{"self":[{"href":"https:\/\/www.unicoda.com\/index.php?rest_route=\/wp\/v2\/posts\/1622","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.unicoda.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.unicoda.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.unicoda.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.unicoda.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=1622"}],"version-history":[{"count":8,"href":"https:\/\/www.unicoda.com\/index.php?rest_route=\/wp\/v2\/posts\/1622\/revisions"}],"predecessor-version":[{"id":1632,"href":"https:\/\/www.unicoda.com\/index.php?rest_route=\/wp\/v2\/posts\/1622\/revisions\/1632"}],"wp:attachment":[{"href":"https:\/\/www.unicoda.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=1622"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.unicoda.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=1622"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.unicoda.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=1622"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}[default]\r\n pattern = .*\r\n retentions = 1s:30m,1m:1d,5m:2y<\/pre>\n
\nIf I was trying to display last hour metrics: nothing.
\nDrawing null as zero was giving me a horizontal line at the bottom of the graph.<\/p>\nThe magic of aggregation<\/h3>\n
[99_default_avg]\r\n pattern = .*\r\n xFilesFactor = 0.5\r\n aggregationMethod = average<\/pre>\n
\nFor interval higher than 30 minutes (and lower than a day), Graphite will gather data based on the aggregation configured. So it will average data and set the value null if it has less than 50% usable values (not null).<\/p>\nThe art of confusion<\/h3>\n
whisper-info.py \/opt\/graphite\/storage\/whisper\/collectd\/test-java01\/cpu-0\/cpu-user.wsp\r\n \r\n maxRetention: 63072000\r\n xFilesFactor: 0.5\r\n aggregationMethod: average\r\n fileSize: 2561812\r\n\r\nArchive 0\r\n retention: 1800\r\n secondsPerPoint: 1\r\n points: 1800\r\n size: 21600\r\n offset: 52\r\nArchive 1\r\n retention: 86400\r\n secondsPerPoint: 60\r\n points: 1440\r\n size: 17280\r\n offset: 21652\r\nArchive 2\r\n retention: 63072000\r\n secondsPerPoint: 300\r\n points: 210240\r\n size: 2522880\r\n offset: 38932<\/pre>\n
\nIf you don’t care about previous data, a good solution is to delete files so that the new parameters will be used (rm -rf \/opt\/graphite\/storage\/whisper\/collectd\/<\/em>). Maybe it’s a little bit overkill, (but easy and fast).<\/p>\n
\nwhisper-resize.py \/opt\/graphite\/storage\/whisper\/collectd\/test-java01\/cpu-0\/cpu-user.wsp 3s:30m,1m:1d,5m:2y –xFilesFactor=0.1<\/em><\/p>\n
\n30m = 1800s
\n1800 \/ 3 = 600<\/p>\n\n
Note<\/h3>\n