{"id":2915,"date":"2017-11-30T15:13:54","date_gmt":"2017-11-30T07:13:54","guid":{"rendered":"http:\/\/cn.hostease.com\/xueyuan\/?p=2915"},"modified":"2017-11-30T15:13:54","modified_gmt":"2017-11-30T07:13:54","slug":"%e9%87%8a%e6%94%belinux%e7%9a%84buffcache","status":"publish","type":"post","link":"https:\/\/cn.hostease.com\/xueyuan\/jishu\/linux\/%e9%87%8a%e6%94%belinux%e7%9a%84buffcache\/","title":{"rendered":"\u91ca\u653eLinux\u7684buff\/cache"},"content":{"rendered":"<p>\u6709\u4e2aLinux\u7684\u670d\u52a1\u5668\uff0c2G\u5185\u5b58\u7684\uff0c\u4eca\u5929\u767b\u4e0a\u53bb\u4e00\u770b\uff0c\u5185\u5b58\u7adf\u7136\u88ab\u5360\u5f97\u6ee1\u6ee1\u7684\u3002<br \/>\nssh\u4e0a\u53bb\u6267\u884c\u4e86free.<\/p>\n<pre><code class=\"hljs cpp\"><span class=\"hljs-built_in\">free<\/span> -m\r\ntotal        used        <span class=\"hljs-built_in\">free<\/span>      shared  buff\/cache   available\r\nMem:           <span class=\"hljs-number\">2000<\/span>         <span class=\"hljs-number\">182<\/span>         <span class=\"hljs-number\">191<\/span>           <span class=\"hljs-number\">3<\/span>        <span class=\"hljs-number\">1625<\/span>        <span class=\"hljs-number\">1614<\/span>\r\nSwap:             <span class=\"hljs-number\">0<\/span>           <span class=\"hljs-number\">0<\/span>           <span class=\"hljs-number\">0<\/span>\r\n<\/code><\/pre>\n<p>\u53d1\u73b0\u5185\u5b58\u5168\u5728\u4e00\u4e2a[buff\/cache]\u91cc.<br \/>\n\u67e5\u8be2\u8d44\u6599\u5f97\u77e5\u53ef\u4ee5\u901a\u8fc7proc\u4e0b\u7684\u4e00\u4e2a\u6587\u4ef6\u91ca\u653e,<br \/>\n\u4ee5\u4e0b\u539f\u6587:<\/p>\n<blockquote><p>\/proc\u662f\u4e00\u4e2a\u865a\u62df\u6587\u4ef6\u7cfb\u7edf,\u6211\u4eec\u53ef\u4ee5\u901a\u8fc7\u5bf9\u5b83\u7684\u8bfb\u5199\u64cd\u4f5c\u505a\u4e3a\u4e0ekernel\u5b9e\u4f53\u95f4\u8fdb\u884c\u901a\u4fe1\u7684\u4e00\u79cd\u624b\u6bb5.\u4e5f\u5c31\u662f\u8bf4\u53ef\u4ee5\u901a\u8fc7\u4fee\u6539\/proc\u4e2d\u7684\u6587\u4ef6,\u6765\u5bf9\u5f53\u524dkernel\u7684\u884c\u4e3a\u505a\u51fa\u8c03\u6574.\u90a3\u4e48\u6211\u4eec\u53ef\u4ee5\u901a\u8fc7\u8c03\u6574\/proc\/sys\/vm\/drop_caches\u6765\u91ca\u653e\u5185\u5b58.\u64cd\u4f5c\u5982\u4e0b:<br \/>\n[<a>root@server<\/a> test]# cat \/proc\/sys\/vm\/drop_caches<br \/>\n0<br \/>\n\u9996\u5148,\/proc\/sys\/vm\/drop_caches\u7684\u503c,\u9ed8\u8ba4\u4e3a0<br \/>\n[<a>root@server<\/a> test]# sync<br \/>\n\u624b\u52a8\u6267\u884csync\u547d\u4ee4(\u63cf\u8ff0:sync \u547d\u4ee4\u8fd0\u884c sync \u5b50\u4f8b\u7a0b\u3002\u5982\u679c\u5fc5\u987b\u505c\u6b62\u7cfb\u7edf\uff0c\u5219\u8fd0\u884c sync \u547d\u4ee4\u4ee5\u786e\u4fdd\u6587\u4ef6\u7cfb\u7edf\u7684\u5b8c\u6574\u6027\u3002sync \u547d\u4ee4\u5c06\u6240\u6709\u672a\u5199\u7684\u7cfb\u7edf\u7f13\u51b2\u533a\u5199\u5230\u78c1\u76d8\u4e2d\uff0c\u5305\u542b\u5df2\u4fee\u6539\u7684 i-node\u3001\u5df2\u5ef6\u8fdf\u7684\u5757 I\/O \u548c\u8bfb\u5199\u6620\u5c04\u6587\u4ef6)<br \/>\n[<a>root@server<\/a> test]# echo 3 &gt; \/proc\/sys\/vm\/drop_caches<br \/>\n[<a>root@server<\/a> test]# cat \/proc\/sys\/vm\/drop_caches<br \/>\n3<br \/>\n\u5c06\/proc\/sys\/vm\/drop_caches\u503c\u8bbe\u4e3a3<br \/>\n[<a>root@server<\/a> test]# free -m<br \/>\ntotal used free shared buffers cached<br \/>\nMem: 249 66 182 0 0 11<br \/>\n-\/+ buffers\/cache: 55 194<br \/>\nSwap: 511 0 511<br \/>\n\u518d\u6765\u8fd0\u884cfree\u547d\u4ee4,\u53d1\u73b0\u73b0\u5728\u7684used\u4e3a66MB,free\u4e3a182MB,buffers\u4e3a0MB,cached\u4e3a11MB.\u90a3\u4e48\u6709\u6548\u7684\u91ca\u653e\u4e86buffer\u548ccache.<\/p><\/blockquote>\n<p>\u6839\u636e\u8d44\u6599,\u53ea\u9700\u8981\u6267\u884c\u4e0b\u97622\u4e2a\u547d\u4ee4,\u5373\u53ef\u91ca\u653e:<\/p>\n<pre class=\"shell\"><code class=\"hljs dts\">sync\r\necho <span class=\"hljs-number\">1<\/span> &gt; <span class=\"hljs-meta-keyword\">\/proc\/<\/span>sys<span class=\"hljs-meta-keyword\">\/vm\/<\/span>drop_caches\r\necho <span class=\"hljs-number\">2<\/span> &gt; <span class=\"hljs-meta-keyword\">\/proc\/<\/span>sys<span class=\"hljs-meta-keyword\">\/vm\/<\/span>drop_caches\r\necho <span class=\"hljs-number\">3<\/span> &gt; <span class=\"hljs-meta-keyword\">\/proc\/<\/span>sys<span class=\"hljs-meta-keyword\">\/vm\/<\/span>drop_caches<\/code><\/pre>\n","protected":false},"excerpt":{"rendered":"<p>\u6709\u4e2aLinux\u7684\u670d\u52a1\u5668\uff0c2G\u5185\u5b58\u7684\uff0c\u4eca\u5929\u767b\u4e0a\u53bb\u4e00\u770b\uff0c\u5185\u5b58\u7adf\u7136\u88ab\u5360\u5f97\u6ee1\u6ee1\u7684\u3002 ssh\u4e0a\u53bb\u6267\u884c\u4e86free. fre &#8230; <a title=\"\u91ca\u653eLinux\u7684buff\/cache\" class=\"read-more\" href=\"https:\/\/cn.hostease.com\/xueyuan\/jishu\/linux\/%e9%87%8a%e6%94%belinux%e7%9a%84buffcache\/\" aria-label=\"\u9605\u8bfb \u91ca\u653eLinux\u7684buff\/cache\">\u9605\u8bfb\u66f4\u591a<\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_jetpack_memberships_contains_paid_content":false,"footnotes":""},"categories":[49],"tags":[805,38],"class_list":["post-2915","post","type-post","status-publish","format-standard","hentry","category-linux","tag-buff","tag-linux"],"aioseo_notices":[],"jetpack_featured_media_url":"","jetpack-related-posts":[],"jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/cn.hostease.com\/xueyuan\/wp-json\/wp\/v2\/posts\/2915","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/cn.hostease.com\/xueyuan\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/cn.hostease.com\/xueyuan\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/cn.hostease.com\/xueyuan\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/cn.hostease.com\/xueyuan\/wp-json\/wp\/v2\/comments?post=2915"}],"version-history":[{"count":1,"href":"https:\/\/cn.hostease.com\/xueyuan\/wp-json\/wp\/v2\/posts\/2915\/revisions"}],"predecessor-version":[{"id":2916,"href":"https:\/\/cn.hostease.com\/xueyuan\/wp-json\/wp\/v2\/posts\/2915\/revisions\/2916"}],"wp:attachment":[{"href":"https:\/\/cn.hostease.com\/xueyuan\/wp-json\/wp\/v2\/media?parent=2915"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/cn.hostease.com\/xueyuan\/wp-json\/wp\/v2\/categories?post=2915"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/cn.hostease.com\/xueyuan\/wp-json\/wp\/v2\/tags?post=2915"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}