{"id":3136,"date":"2013-05-30T17:16:46","date_gmt":"2013-05-30T09:16:46","guid":{"rendered":"http:\/\/staff.ie.cuhk.edu.hk\/~sfluk\/wordpress\/?p=3136"},"modified":"2013-06-11T16:54:23","modified_gmt":"2013-06-11T08:54:23","slug":"use-noop-io-scheduler-for-virtualized-linux-guest-with-kernel-2-6-guest-on-vmware","status":"publish","type":"post","link":"https:\/\/staff.ie.cuhk.edu.hk\/~sfluk\/wordpress\/?p=3136","title":{"rendered":"Use NOOP I\/O Scheduler for virtualized Linux guest with kernel 2.6 guest on vmware"},"content":{"rendered":"<p>Refer to <a href=\"http:\/\/kb.vmware.com\/selfservice\/microsites\/search.do?language=en_US&amp;cmd=displayKC&amp;externalId=2011861\">http:\/\/kb.vmware.com\/selfservice\/microsites\/search.do?language=en_US&amp;cmd=displayKC&amp;externalId=2011861<\/a><\/p>\n<ul>\n<li>The scheduler can be set for each hard disk unit. To check which scheduler is being used for particular drive, run this command:\n<p><span style=\"font-size: x-small;\">cat \/sys\/block\/disk\/queue\/scheduler<\/span><\/p>\n<p>For example, to check the current I\/O scheduler for <span style=\"font-size: x-small;\">sda<\/span>:<\/p>\n<p><span style=\"font-size: x-small;\"># cat \/sys\/block\/sda\/queue\/scheduler<br \/>\n[noop] anticipatory deadline cfq<\/span><\/p>\n<p>In this example, the <span style=\"font-size: x-small;\">sda<\/span> drive scheduler is set to NOOP.<\/li>\n<li>To change the scheduler on a running system, run this command:\n<p><span style=\"font-size: x-small;\"># echo scheduler &gt; \/sys\/block\/disk\/queue\/scheduler<\/span><\/p>\n<p>For example, to set the <span style=\"font-size: x-small;\">sda<\/span> I\/O scheduler to NOOP:<\/p>\n<p><span style=\"font-size: x-small;\"># echo noop &gt; \/sys\/block\/sda\/queue\/scheduler<\/span><\/p>\n<p>Note: This command will not change the scheduler permanently. The scheduler will be reset to the default on reboot. To make the system use a specific scheduler by default, add an <span style=\"font-size: x-small;\">elevator<\/span> parameter to the default kernel entry in the GRUB boot loader <span style=\"font-size: x-small;\">menu.lst<\/span> file.<\/p>\n<p>For example, to make NOOP the default scheduler for the system, the <span style=\"font-size: x-small;\">\/boot\/grub\/menu.lst<\/span> kernel entry would look like this:<\/p>\n<p><span style=\"font-size: x-small;\">title CentOS (2.6.18-128.4.1.el5)<br \/>\nroot (hd0,0)<br \/>\nkernel \/vmlinuz-2.6.18-128.4.1.el5 ro root=\/dev\/VolGroup00\/LogVol00 elevator=noop<br \/>\ninitrd \/initrd-2.6.18-128.4.1.el5.img<\/span><\/p>\n<p>With the <span style=\"font-size: x-small;\">elevator<\/span> parameter in place, the system will set the I\/O scheduler to the one specified on every boot.<\/li>\n<\/ul>\n","protected":false},"excerpt":{"rendered":"<p>Refer to http:\/\/kb.vmware.com\/selfservice\/microsites\/search.do?language=en_US&amp;cmd=displayKC&amp;externalId=2011861<\/p>\n<p> The scheduler can be set for each hard disk unit. To check which scheduler is being used for particular drive, run this command: <\/p>\n<p>cat \/sys\/block\/disk\/queue\/scheduler<\/p>\n<p>For example, to check the current I\/O scheduler for sda:<\/p>\n<p># cat \/sys\/block\/sda\/queue\/scheduler [noop] anticipatory deadline cfq<\/p>\n<p>In this example, the sda drive scheduler is set to [&#8230;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"ngg_post_thumbnail":0,"footnotes":""},"categories":[3],"tags":[57,106,18],"class_list":["post-3136","post","type-post","status-publish","format-standard","hentry","category-computer","tag-linux","tag-tuning","tag-vmware","odd"],"_links":{"self":[{"href":"https:\/\/staff.ie.cuhk.edu.hk\/~sfluk\/wordpress\/index.php?rest_route=\/wp\/v2\/posts\/3136","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/staff.ie.cuhk.edu.hk\/~sfluk\/wordpress\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/staff.ie.cuhk.edu.hk\/~sfluk\/wordpress\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/staff.ie.cuhk.edu.hk\/~sfluk\/wordpress\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/staff.ie.cuhk.edu.hk\/~sfluk\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=3136"}],"version-history":[{"count":3,"href":"https:\/\/staff.ie.cuhk.edu.hk\/~sfluk\/wordpress\/index.php?rest_route=\/wp\/v2\/posts\/3136\/revisions"}],"predecessor-version":[{"id":3138,"href":"https:\/\/staff.ie.cuhk.edu.hk\/~sfluk\/wordpress\/index.php?rest_route=\/wp\/v2\/posts\/3136\/revisions\/3138"}],"wp:attachment":[{"href":"https:\/\/staff.ie.cuhk.edu.hk\/~sfluk\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=3136"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/staff.ie.cuhk.edu.hk\/~sfluk\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=3136"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/staff.ie.cuhk.edu.hk\/~sfluk\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=3136"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}