{"id":508,"date":"2014-04-10T01:48:48","date_gmt":"2014-04-10T01:48:48","guid":{"rendered":"http:\/\/www.selinuxplus.com\/?p=508"},"modified":"2014-04-10T01:48:48","modified_gmt":"2014-04-10T01:48:48","slug":"ceph%e5%ad%a6%e4%b9%a0-8crush%e7%ae%97%e6%b3%953","status":"publish","type":"post","link":"http:\/\/www.selinuxplus.com\/?p=508","title":{"rendered":"[ceph\u5b66\u4e60-8]crush\u7b97\u6cd5(3)"},"content":{"rendered":"

\u51b2\u7a81\u3001\u6545\u969c\u3001\u548c\u8d85\u8f7d
\n select\uff08n,t)\u64cd\u4f5c\u53ef\u80fd\u4e3a\u4e86\u5b9a\u4f4dn\u4e2a\u4e0d\u76f8\u540c\u7684t\u7c7b\u578b\u7684item\uff0c\u800c\u4ece\u8d77\u70b9\u5f00\u59cb\u5411\u4e0b\u904d\u5386\u800c\u7ecf\u8fc7\u8bb8\u591a\u5c42\uff0c\u9012\u5f52\u8fc7\u7a0b\u7684\u6b21\u6570\u6709r=1,..n\u786e\u5b9a\uff0cn\u662f\u9009\u62e9\u526f\u672c\u7684\u4e2a\u6570\u3002\u5728\u5904\u7406\u8fc7\u7a0b\u4e2d\uff0cCRUSH\u53ef\u80fd\u4f1a\u6709\u4e0b\u9762\u4e09\u4e2a\u4e0d\u540c\u7684\u539f\u56e0\u800c\u7528\u4e8e\u4fee\u6539\u8fc7\u7684\u8f93\u5165r’\u6765\u62d2\u7edd\u5e76\u91cd\u9009\u9879\uff0c\u67d0\u4e2aitem\u5df2\u7ecf\u5728\u5f53\u524d\u7684\u96c6\u5408\u4e2d\uff08\u53d1\u751f\u51b2\u7a81\uff0cselect(n,t)\u7684\u7ed3\u679c\u5fc5\u987b\u662f\u5404\u4e0d\u76f8\u540c\u7684\uff09\uff1b\u6709\u4e00\u4e2a\u8bbe\u5907\u5931\u6548\u4e86\uff0c\u6709\u4e00\u4e2a\u8bbe\u5907\u8d85\u8f7d\u3002\u5931\u6548\u6216\u8d85\u8f7d\u7684\u8bbe\u5907\u90fd\u4f1a\u5728Cluster Map\u4e2d\u8fdb\u884c\u76f8\u5e94\u7684\u6807\u8bb0\uff0c\u4f46\u4e3a\u4e86\u907f\u514d\u4e0d\u5fc5\u8981\u7684\u6570\u636e\u8fc1\u79fb\uff0c\u4e0d\u540c\u4ece\u5c42\u6b21\u7ed3\u6784\u4e2d\u79fb\u9664\u5b83\u4eec\u3002CRUSH\u901a\u8fc7\u6839\u636eCluster Map\u4e2d\u6307\u5b9a\u7684\u6982\u7387\u4f2a\u968f\u673a\u7684\u62d2\u7edd\u8d85\u8f7d\u7684\u8bbe\u5907\uff0c\u6765\u9009\u62e9\u6027\u7684\u8f6c\u79fb\u6b64\u8d85\u8f7ddevice\u4e0a\u7684\u5c11\u90e8\u5206\u6570\u636e\u3002\u8fd9\u4e2a\u6982\u7387\u5219\u662f\u4e0e\u62a5\u544a\u7684\u8d85\u8f7d\u60c5\u51b5\u6709\u5173\u7684\u3002\u5bf9\u4e8e\u5931\u6548\u6216\u8d85\u8f7d\u7684\u8bbe\u5907\u3001CRUSH\u901a\u8fc7\u91cd\u65b0\u542f\u52a8select\uff08n,t)\u5f00\u59cb\u90e8\u5206\u9012\u5f52\u8fc7\u7a0b\uff0c\u5747\u5300\u7684\u5728\u5b58\u50a8\u96c6\u7fa4\u4e2d\u91cd\u65b0\u5206\u5e03\u8fd9\u4e9bitem\u3002\u800c\u5bf9\u5e94\u51b2\u7a81\u7684\u9752\u7750\uff0c\u5219\u5728\u9012\u5f52\u5185\u5c42\u4f7f\u7528r’\u66ff\u6362r\u6765\u8fdb\u884c\u5c40\u90e8\u641c\u7d22\u3002\u4e0d\u81f3\u4e8e\u5728\u90a3\u4e9b\u5f88\u53ef\u80fd\u53d1\u751f\u51b2\u7a81\u7684\u5b50\u6811\u4e2d\uff08bucket\u5bb9\u91cf\u5c0f\u4e8en\uff09\u6539\u53d8\u603b\u4f53\u6570\u636e\u5206\u5e03\u3002<\/p>\n

\u51b2\u7a81\uff1a\u8fd9\u4e2aitem\u5df2\u7ecf\u5728\u5411\u91cfi\u4e2d\uff0c\u5df2\u88ab\u9009\u62e9\uff0c\u4f7f\u7528r'(r’\u548cr\u3001\u51fa\u9519\u6b21\u6570\uff0cfirstn\u53c2\u6570\uff09\u505a\u4e3a\u65b0\u7684\u53c2\u6570\u9009\u62e9item\uff08\u5c40\u90e8\u9009\u62e9\uff09
\n \u6545\u969c\uff1a\u8bbe\u5907\u6545\u969c\uff0c\u4e0d\u80fd\u88ab\u9009\u62e9\u3002
\n \u8d85\u8f7d\uff1a\u8bbe\u5907\u4f7f\u7528\u5bb9\u91cf\u8d85\u8fc7\u8b66\u6212\u7ebf\u3001\u6ca1\u6709\u5269\u4f59\u7a7a\u95f4\u4fdd\u5b58\u6570\u636e\u3002
\n \u5176\u4e2d\u6545\u969c\u548c\u8d85\u8f7d\u8bbe\u5907\u4f1a\u5728clustermap\u4e0a\u6807\u8bb0\uff0c\u4e3a\u4e86\u4e0d\u5fc5\u8981\u7684\u6570\u636e\u8fc1\u79fb\uff0c\u4e0d\u4f1a\u4ece\u5c42\u6b21\u7ed3\u6784\u4e2d\u79fb\u9664\u5b83\u4eec\u3002<\/p>\n

\u526f\u672c\u6392\u5e8f
\n \u5728\u4e3b\u62f7\u8d1d\u526f\u672c\u6a21\u5f0f\u4e2d\uff0c\u53d1\u751f\u6545\u969c\u65f6\uff0c\u8ba9\u4e4b\u524d\u7684\u526f\u672c\u76ee\u6807\u6210\u4e3a\u65b0\u7684\u4e3b\u62f7\u8d1d\uff0c\u5728\u8fd9\u79cd\u60c5\u51b5\u4e0b\uff0cCRUSH\u53ef\u4ee5\u901a\u8fc7r’=r+f\u8fdb\u884c\u91cd\u9009\uff0c\u6765\u4f7f\u7528\u201d\u524dn\u4e2a\u201c\u5408\u9002\u7684\u76ee\u6807\uff0cf\u662f\u5f53\u524dselect(n,t)\u64cd\u4f5c\u4e2d\u786e\u5b9a\u653e\u7f6e\u4f4d\u7f6e\u5931\u8d25\u7684\u6b21\u6570\u3002\u800c\u5bf9\u4e8e\u5947\u5076\u6821\u9a8c\u7801\u6216\u64e6\u9664\u7801\u6a21\u5f0f\uff0cCRUSH\u7b97\u6cd5\u8f93\u51fa\u7684\u5b58\u50a8\u8bbe\u5907\u7684\u987a\u5e8f\u81f3\u5173\u91cd\u8981\uff0c\u56e0\u4e3a\u6bcf\u4e2a\u76ee\u6807\u90fd\u5b58\u653e\u4e86\u6570\u636e\u5bf9\u8c61\u7684\u4e0d\u540c\u6bd4\u7279\u4f4d\uff0c\u7279\u522b\u7684\uff0c\u5f53\u67d0\u4e2a\u5b58\u50a8\u8bbe\u5907\u53d1\u751f\u6545\u969c\u65f6\uff0c\u5b83\u9700\u8981\u5728CRUSH\u7684\u8f93\u51fa\u5217\u8868R(\u5411\u91cfR)\u7684\u5bf9\u5e94\u4f4d\u7f6e\u4e0a\u88ab\u66ff\u6362\uff0c\u5176\u4ed6\u5217\u8868\u4e2d\u7684\u8bbe\u5907\u8981\u7ef4\u6301\u4f4d\u7f6e\u4e0d\u53d8\uff08\u4f4d\u7f6e\u662f\u6307\u5411\u91cfR\u5bf9\u5e94\u7684\u4f4d\u7f6e\uff09\u8fd9\u79cd\u60c5\u51b5\u4e0b\uff0cCRUSH\u901a\u8fc7r\u2019=r+fn\u8fdb\u884c\u91cd\u9009\uff0c\u5176\u4e2df\u662f\u7b2cr\u6b21\u8fed\u4ee3\u65f6\u5931\u8d25\u7684\u6b21\u6570\u3002\u8fd9\u6837\u5c31\u662f\u4e3a\u6bcf\u4e00\u4e2a\u5411\u91cf\u4f4d\u7f6e\u4e0a\u7684item\u5b9a\u4e49\u4e86\u4e00\u7cfb\u5217\u7684\u5019\u9009item\u3002\u6bcf\u4e2a\u5019\u9009item\u4e0e\u5176\u4ed6\u4f4d\u7f6e\u4e0a\u7684\u5019\u9009item\u662f\u65e0\u5173\u7684\u3002\u76f8\u6bd4\uff0cRUSH\u5bf9\u5e94\u53d1\u751f\u6545\u969c\u7684\u8bbe\u5907\u6ca1\u6709\u7279\u6b8a\u5904\u7406\uff0c\u5c31\u50cf\u5176\u4ed6\u73b0\u6709\u7684\u6563\u5217\u5206\u5e03\u5f0f\u51fd\u6570\uff0c\u5b83\u9690\u5f0f\u7684\u5047\u8bbe\u4f7f\u7528\u201d\u524dn\u4e2a”\u7684\u7b56\u7565\u5728\u7ed3\u679c\u4e2d\u8df3\u8fc7\u5931\u6548\u7684\u8bbe\u5907\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"

\u51b2\u7a81\u3001\u6545\u969c\u3001\u548c\u8d85\u8f7d select\uff08n,t)\u64cd\u4f5c\u53ef\u80fd…<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[84,83],"tags":[180,97],"_links":{"self":[{"href":"http:\/\/www.selinuxplus.com\/index.php?rest_route=\/wp\/v2\/posts\/508"}],"collection":[{"href":"http:\/\/www.selinuxplus.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/www.selinuxplus.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/www.selinuxplus.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/www.selinuxplus.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=508"}],"version-history":[{"count":1,"href":"http:\/\/www.selinuxplus.com\/index.php?rest_route=\/wp\/v2\/posts\/508\/revisions"}],"predecessor-version":[{"id":509,"href":"http:\/\/www.selinuxplus.com\/index.php?rest_route=\/wp\/v2\/posts\/508\/revisions\/509"}],"wp:attachment":[{"href":"http:\/\/www.selinuxplus.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=508"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/www.selinuxplus.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=508"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/www.selinuxplus.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=508"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}