{"id":1817,"date":"2009-05-04T20:27:38","date_gmt":"2009-05-05T00:27:38","guid":{"rendered":"http:\/\/blogs.n1zyy.com\/n1zyy\/?p=1817"},"modified":"2009-05-04T20:27:38","modified_gmt":"2009-05-05T00:27:38","slug":"io-under-linux","status":"publish","type":"post","link":"https:\/\/blogs.n1zyy.com\/n1zyy\/2009\/05\/04\/io-under-linux\/","title":{"rendered":"I\/O Under Linux"},"content":{"rendered":"<p>I really didn&#8217;t intend to do a post focusing on I\/O, an absurdly boring topic to most people, but I&#8217;ve recently stumbled across a few related tools that Linux users might find interesting.<\/p>\n<ul>\n<li><b>ionice<\/b> is standard on newish CentOS, at least. I ran into a situation where I have to back up an active NFS server. This sounds like it could spell disaster, with <tt>nfsd<\/tt> needing fast access and <tt>rsync<\/tt> wanting to touch hundreds of gigs of data as fast as it can. The <tt>nice<\/tt> command is meant to limit number-crunching, not disk-spinning. But never fear: <tt>ionice<\/tt> is here! Slapping <tt>ionice -c2 -n7<\/tt> in front of my mammoth <tt>rsync<\/tt> seems to have done the trick: NFS stayed peppy for the duration of the transfer.<\/li>\n<li>Something that I forget often: if you&#8217;re copying files around for the first time, or it&#8217;s been <i>so<\/i> long that the files are wholly different, use straight <tt>scp<\/tt> or something similar, not <tt>rsync<\/tt>. I don&#8217;t have the numbers to back it up, but <tt>rsync<\/tt> is good at copying over only what&#8217;s changed, but it&#8217;s a waste of time if the source and destination files are completely different.<\/li>\n<li><tt>dstat<\/tt> is a colorful replacement* for <tt>iostat<\/tt>. (* because it&#8217;s not necessarily a replacement, so much as a tool folding <tt>iostat<\/tt>, <tt>vmstat<\/tt>, and some others into one.) You can read the man page for <tt>dstat<\/tt> to find out plenty, but just typing <tt>dstat<\/tt> and letting it run is a good enough starting point. Network and interrupt stats, too!<\/li>\n<li>Some of this interest comes from perusing the slideshows on the <a href=\"http:\/\/conferences.percona.com\/percona-performance-conference-2009\/schedule.html\">Percona Conference<\/a> site. Also worth checking out are their <a href=\"http:\/\/www.percona.com\/presentations.html\">presentation slides<\/a> in general.<\/li>\n<\/ul>","protected":false},"excerpt":{"rendered":"<p>I really didn&#8217;t intend to do a post focusing on I\/O, an absurdly boring topic to most people, but I&#8217;ve recently stumbled across a few related tools that Linux users might find interesting. ionice is standard on newish CentOS, at &hellip; <a href=\"https:\/\/blogs.n1zyy.com\/n1zyy\/2009\/05\/04\/io-under-linux\/\">Continue reading <span class=\"meta-nav\">&rarr;<\/span><\/a><\/p>","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-1817","post","type-post","status-publish","format-standard","hentry","category-uncategorized"],"_links":{"self":[{"href":"https:\/\/blogs.n1zyy.com\/n1zyy\/wp-json\/wp\/v2\/posts\/1817","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/blogs.n1zyy.com\/n1zyy\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/blogs.n1zyy.com\/n1zyy\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/blogs.n1zyy.com\/n1zyy\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/blogs.n1zyy.com\/n1zyy\/wp-json\/wp\/v2\/comments?post=1817"}],"version-history":[{"count":0,"href":"https:\/\/blogs.n1zyy.com\/n1zyy\/wp-json\/wp\/v2\/posts\/1817\/revisions"}],"wp:attachment":[{"href":"https:\/\/blogs.n1zyy.com\/n1zyy\/wp-json\/wp\/v2\/media?parent=1817"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blogs.n1zyy.com\/n1zyy\/wp-json\/wp\/v2\/categories?post=1817"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blogs.n1zyy.com\/n1zyy\/wp-json\/wp\/v2\/tags?post=1817"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}