{"id":227,"date":"2015-09-13T01:51:17","date_gmt":"2015-09-12T23:51:17","guid":{"rendered":"https:\/\/blog.unetresgrossebite.com\/?p=227"},"modified":"2015-09-13T01:51:59","modified_gmt":"2015-09-12T23:51:59","slug":"munin-io-latencies","status":"publish","type":"post","link":"https:\/\/blog.unetresgrossebite.com\/?p=227","title":{"rendered":"Munin I\/O latencies"},"content":{"rendered":"

Dealing with large amounts of hosts and probes to graph, or sometimes just disks with poor performances, you may see munin loading and your system struggling with I\/O waits.<\/p>\n

It’s not the first time I have to deal with such problems. I’ve used tmpfs and hourly crontabs saving rrd data, SSD, RAID 0+1, … There’s lots of ways, to mitigate with such troubles.
\nThough today, I decided to have an other look on google, and found out about rrdcached<\/em>.<\/p>\n

Switching to\u00a0rrdcached on an existing munin setup\u00a0is pretty straight forward: install the package, feed the service the proper options to use with munin. The you’ll need to update your munin.conf, setting\u00a0rrdcached_socket<\/em> to the socket created by rrdcached. That’s it.
\nFrom there, you could consider updating munin jobs, so that munin-html and munin-graph are not run every 5 minutes, which would drastically lower your I\/O. Alternatively, you may mount your munin www directory using tmpfs: your rrd data remain either cached or written on disk,\u00a0thus on the next munin-html\/munin-graph job, your munin DocumentRoot\u00a0is completely rewritten anyway.<\/p>\n

\"Munin<\/a>

Munin RRDCache – vmstat<\/p><\/div>\n

\"Munin<\/a>

Munin RRDCache – CPU usage<\/p><\/div>\n

\"Munin<\/a>

Munin RRDCache – load average<\/p><\/div>\n

\"Munin<\/a>

Munin RRDCache – processes priority<\/p><\/div>\n

\"Munin<\/a>

Munin RRDCache – diskstats<\/p><\/div>\n

\"Munin<\/a>

Munin RRDCache – disk latency<\/p><\/div>\n","protected":false},"excerpt":{"rendered":"

Dealing with large amounts of hosts and probes to graph, or sometimes just disks with poor performances, you may see munin loading and your system struggling with I\/O waits. It’s not the first time I have to deal with such problems. I’ve used tmpfs and hourly crontabs saving rrd data, SSD, RAID 0+1, … There’s […]<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[8,6,2],"tags":[],"_links":{"self":[{"href":"https:\/\/blog.unetresgrossebite.com\/index.php?rest_route=\/wp\/v2\/posts\/227"}],"collection":[{"href":"https:\/\/blog.unetresgrossebite.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/blog.unetresgrossebite.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/blog.unetresgrossebite.com\/index.php?rest_route=\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/blog.unetresgrossebite.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=227"}],"version-history":[{"count":1,"href":"https:\/\/blog.unetresgrossebite.com\/index.php?rest_route=\/wp\/v2\/posts\/227\/revisions"}],"predecessor-version":[{"id":234,"href":"https:\/\/blog.unetresgrossebite.com\/index.php?rest_route=\/wp\/v2\/posts\/227\/revisions\/234"}],"wp:attachment":[{"href":"https:\/\/blog.unetresgrossebite.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=227"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blog.unetresgrossebite.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=227"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blog.unetresgrossebite.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=227"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}