{"id":471,"date":"2011-01-28T00:30:38","date_gmt":"2011-11-25T21:51:50","guid":{"rendered":"http:\/\/kraftek.com\/blog\/disk-contention\/"},"modified":"2011-01-28T00:30:38","modified_gmt":"2011-11-25T21:51:50","slug":"disk-contention","status":"publish","type":"post","link":"\/blog\/index.php\/disk-contention\/","title":{"rendered":"Disk contention"},"content":{"rendered":"<p>To see if we have disk contention problems we&#8217;d take a look at an iostat. if asvc_t &gt;50 for sustained periods, the system<br \/>\nhas disk contention problems.<\/p>\n<pre>[root@ehrpitlin001 ~]# iostat -x 3 10000 | awk '$11&gt;=50'\nDevice:\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 rrqm\/s\u00a0\u00a0 wrqm\/s\u00a0\u00a0 r\/s\u00a0\u00a0 w\/s\u00a0\u00a0 rsec\/s\u00a0\u00a0 wsec\/s avgrq-sz avgqu-sz\u00a0\u00a0 await\u00a0 svctm\u00a0 %util<\/pre>\n<p>we can also check if the %wio cpu is &gt; 5% for more than a minute constantly<\/p>\n<pre>[root@ehrpitlin001 ~]# vmstat 1 3000 | awk '$16&gt;=5'\n\u00a0r\u00a0 b\u00a0\u00a0 swpd\u00a0\u00a0 free\u00a0\u00a0 buff\u00a0 cache\u00a0\u00a0 si\u00a0\u00a0 so\u00a0\u00a0\u00a0 bi\u00a0\u00a0\u00a0 bo\u00a0\u00a0 in\u00a0\u00a0 cs us sy id wa st\n\u00a0r\u00a0 b\u00a0\u00a0 swpd\u00a0\u00a0 free\u00a0\u00a0 buff\u00a0 cache\u00a0\u00a0 si\u00a0\u00a0 so\u00a0\u00a0\u00a0 bi\u00a0\u00a0\u00a0 bo\u00a0\u00a0 in\u00a0\u00a0 cs us sy id wa st\n\u00a0r\u00a0 b\u00a0\u00a0 swpd\u00a0\u00a0 free\u00a0\u00a0 buff\u00a0 cache\u00a0\u00a0 si\u00a0\u00a0 so\u00a0\u00a0\u00a0 bi\u00a0\u00a0\u00a0 bo\u00a0\u00a0 in\u00a0\u00a0 cs us sy id wa st\n\u00a0r\u00a0 b\u00a0\u00a0 swpd\u00a0\u00a0 free\u00a0\u00a0 buff\u00a0 cache\u00a0\u00a0 si\u00a0\u00a0 so\u00a0\u00a0\u00a0 bi\u00a0\u00a0\u00a0 bo\u00a0\u00a0 in\u00a0\u00a0 cs us sy id wa st<\/pre>\n<p>if we have SAR setup we could check it<\/p>\n<pre>[root@ehrpitlin001 ~]# sar | awk '$7&gt;=3{print}' | head -5\n12:10:01 AM\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 all\u00a0\u00a0\u00a0\u00a0\u00a0 4.93\u00a0\u00a0\u00a0\u00a0\u00a0 0.00\u00a0\u00a0\u00a0\u00a0\u00a0 2.00\u00a0\u00a0\u00a0\u00a0 11.84\u00a0\u00a0\u00a0\u00a0\u00a0 0.00\u00a0\u00a0\u00a0\u00a0 81.23\n12:20:01 AM\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 all\u00a0\u00a0\u00a0\u00a0 22.83\u00a0\u00a0\u00a0\u00a0\u00a0 0.00\u00a0\u00a0\u00a0\u00a0\u00a0 4.96\u00a0\u00a0\u00a0\u00a0 14.90\u00a0\u00a0\u00a0\u00a0\u00a0 0.00\u00a0\u00a0\u00a0\u00a0 57.31\n12:30:01 AM\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 all\u00a0\u00a0\u00a0\u00a0 37.14\u00a0\u00a0\u00a0\u00a0\u00a0 0.00\u00a0\u00a0\u00a0\u00a0\u00a0 3.83\u00a0\u00a0\u00a0\u00a0 11.84\u00a0\u00a0\u00a0\u00a0\u00a0 0.00\u00a0\u00a0\u00a0\u00a0 47.19\n12:40:01 AM\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 all\u00a0\u00a0\u00a0\u00a0 44.26\u00a0\u00a0\u00a0\u00a0\u00a0 0.00\u00a0\u00a0\u00a0\u00a0\u00a0 3.88\u00a0\u00a0\u00a0\u00a0 12.71\u00a0\u00a0\u00a0\u00a0\u00a0 0.00\u00a0\u00a0\u00a0\u00a0 39.16\n12:50:01 AM\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 all\u00a0\u00a0\u00a0\u00a0 48.83\u00a0\u00a0\u00a0\u00a0\u00a0 0.03\u00a0\u00a0\u00a0\u00a0\u00a0 3.57\u00a0\u00a0\u00a0\u00a0\u00a0 9.25\u00a0\u00a0\u00a0\u00a0\u00a0 0.00\u00a0\u00a0\u00a0\u00a0 38.32\n\n<\/pre>\n","protected":false},"excerpt":{"rendered":"<p>To see if we have disk contention problems we&#8217;d take a look at an iostat. if asvc_t &gt;50 for sustained periods, the system has disk contention problems. [root@ehrpitlin001 ~]# iostat -x 3 10000 | awk &#8216;$11&gt;=50&#8217; Device:\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 rrqm\/s\u00a0\u00a0 wrqm\/s\u00a0\u00a0 r\/s\u00a0\u00a0 w\/s\u00a0\u00a0 rsec\/s\u00a0\u00a0 wsec\/s avgrq-sz avgqu-sz\u00a0\u00a0 await\u00a0 svctm\u00a0 %util we can also check if the %wio [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-471","post","type-post","status-publish","format-standard","hentry","category-uncategorized"],"_links":{"self":[{"href":"\/blog\/index.php\/wp-json\/wp\/v2\/posts\/471","targetHints":{"allow":["GET"]}}],"collection":[{"href":"\/blog\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"\/blog\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"\/blog\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"\/blog\/index.php\/wp-json\/wp\/v2\/comments?post=471"}],"version-history":[{"count":0,"href":"\/blog\/index.php\/wp-json\/wp\/v2\/posts\/471\/revisions"}],"wp:attachment":[{"href":"\/blog\/index.php\/wp-json\/wp\/v2\/media?parent=471"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"\/blog\/index.php\/wp-json\/wp\/v2\/categories?post=471"},{"taxonomy":"post_tag","embeddable":true,"href":"\/blog\/index.php\/wp-json\/wp\/v2\/tags?post=471"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}