{"id":1648,"date":"2013-02-08T11:58:05","date_gmt":"2013-02-08T16:58:05","guid":{"rendered":"http:\/\/www.kickflop.net\/blog\/?p=1648"},"modified":"2013-02-08T12:50:05","modified_gmt":"2013-02-08T17:50:05","slug":"cifs-read-performance-on-linux-3-2","status":"publish","type":"post","link":"https:\/\/www.kickflop.net\/blog\/2013\/02\/08\/cifs-read-performance-on-linux-3-2\/","title":{"rendered":"CIFS read performance on Linux < 3.2"},"content":{"rendered":"

Here’s what you can expect from read performance using the Linux CIFS kernel module prior to kernel 3.2.<\/p>\n

See the ‘rsync’ graph in the lower right.<\/p>\n

\"Abysmal<\/a><\/p>\n

Relevant context:<\/p>\n

    \n
  1. Each of the colors in the rsync graph represent remote WAN sites. Each data point represents a transfer of ~200MB.<\/li>\n
  2. No amount of dickering with the cifs.ko<\/code> kernel module options improved anything<\/li>\n
  3. All sites have at least 1.5Mbps links<\/li>\n
  4. An HTTP get to each remote site ran at ~900kbps<\/li>\n
  5. Using a Windows 2008 client to each remote site’s CIFS share gave ~940kbps<\/li>\n
  6. Performance did not improve when using cp<\/code> in place of rsync<\/code>, nor did it improve with tweaks to the rsync options.<\/li>\n
  7. The client of the CIFS shares was 96% CPU idle. A textbook case for illustrating to novices the reduced value of looking at load averages (see graph) to indicate how hard a host is working. The CPU graph was removed as it was irrelevant.<\/li>\n<\/ol>\n

    Thankfully, this is a largely solved issue and we’ll see it in future distributions. Here is the thread from the linux-cifs<\/a> list.<\/p>\n","protected":false},"excerpt":{"rendered":"

    A story of technical constraints<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[11,48],"tags":[],"class_list":["post-1648","post","type-post","status-publish","format-standard","hentry","category-sysadmin","category-unixlinux"],"_links":{"self":[{"href":"https:\/\/www.kickflop.net\/blog\/wp-json\/wp\/v2\/posts\/1648","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.kickflop.net\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.kickflop.net\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.kickflop.net\/blog\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.kickflop.net\/blog\/wp-json\/wp\/v2\/comments?post=1648"}],"version-history":[{"count":11,"href":"https:\/\/www.kickflop.net\/blog\/wp-json\/wp\/v2\/posts\/1648\/revisions"}],"predecessor-version":[{"id":1660,"href":"https:\/\/www.kickflop.net\/blog\/wp-json\/wp\/v2\/posts\/1648\/revisions\/1660"}],"wp:attachment":[{"href":"https:\/\/www.kickflop.net\/blog\/wp-json\/wp\/v2\/media?parent=1648"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.kickflop.net\/blog\/wp-json\/wp\/v2\/categories?post=1648"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.kickflop.net\/blog\/wp-json\/wp\/v2\/tags?post=1648"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}