Linux 删除大量小文件的两种方案

环境：RHEL6.5+Oracle11.2.0.4需求：使用df-i巡检发现Inodes使用率过高，需要清理删除文件来解决。如果Inodes满，该目录将不能写，即使df-h查看还有剩余空间。1.问题现象Oracle的adump下记录的是sys的登陆审计信息，特点是小碎文件非常多，经常会遇到使用rm-rf*命令删除不了，报错-bash:/bin/rm:Argumentlisttoolong。这是因为通配符*在执行时会替换为具体的文件名，例如rm-rffile1file2file3...，如果文件数量过多，就容易出现这个错误。比如在下面的环境中，adump目录下文件已达到114万+，执行rm-rf*命令时就会报这个错误：[oracle@jystdrac2adump]$pwd/opt/app/oracle/admin/crmdb/adump[oracle@jystdrac2adump]$ls|wc-l1149787[oracle@jystdrac2adump]$rm-rf*-bash:/bin/rm:Argumentlisttoolong[oracle@jystdrac2adump]$du-sh4.4G2.解决方案清楚了问题现象，解决方案就从除去rm-rf*命令的方式之外，还有哪些方法可用，如果通过网络搜索，可能会找到结合find命令再去执行rm的方式，但其实效率非常差，具体写法这里就不列出了，因为我们通常也不会这样处理。那么如何较为效率的删除大批小文件呢？结合网络的经验，并实测验证，最终总结了两种常见的解决方案，效率上也都尚可。方案一：巧用rsync的方式达到删除目的建立一个空文件夹，使用rsync--delete-before-d<空文件夹><需要清理删除小文件的目录>命令最终达到删除大批小文件的目的。下面演示具体操作：[oracle@jystdrac2adump]$mkdir/data/null[oracle@jystdrac2adump]$ls-l/data/nulltotal0[oracle@jystdrac2~]$nohuprsync--delete-before-d/data/null//opt/app/oracle/admin/crmdb/adump/&使用manrsync查看rsync命令相关的参数说明如下：-d,--dirstransferdirectorieswithoutrecursing--delete-beforereceiverdeletesbeforetransfer(default)方案二：使用find命令的delete参数使用find<需要清理删除小文件的目录>-typef-delete命令直接删除大批小文件。使用manfind查看find命令相关的参数说明如下：-typecFileisoftypec:bblock(buffered)specialccharacter(unbuffered)specialddirectorypnamedpipe(FIFO)fregularfilelsymboliclink;thisisnevertrueifthe-Loptionorthe-followoptionisineffect,unlessthesymboliclinkisbroken.Ifyouwanttosearchforsymboliclinkswhen-Lisineffect,use-xtype.ssocketDdoor(Solaris)-deleteDeletefiles;trueifremovalsucceeded.Iftheremovalfailed,anerrormessageisissued.If-deletefails,find’sexitstatuswillbenonzero(wheniteventuallyexits).Useof-deleteautomaticallyturnsonthe‘-depth’option.Warnings:Don’tforgetthatthefindcommandlineisevaluatedasanexpression,soputting-deletefirstwillmakefindtrytodeleteeverythingbelowthestartingpointsyouspecified.Whentestingafindcommandlinethatyoulaterintendtousewith-delete,youshouldexplicitlyspec-ify-depthinordertoavoidlatersurprises.Because-deleteimplies-depth,youcannotusefullyuse-pruneand-deletetogether.下面演示具体操作：[oracle@jystdrac1adump]$nohupfind/opt/app/oracle/admin/crmdb/adump/-typef-delete&可以参考下面的命令来简单监控删除过程中Inodes使用率的变化：whiletrue;dodf-i/;sleep10;done比如我这里节点jystdrac1使用的find方法，节点jystdrac2使用的rsync方法，实际观察Inodes释放速度区别并不大：#使用的find方法，观察Inodes释放速度：[oracle@jystdrac1~]$whiletrue;dodf-i/;sleep10;doneFilesystemInodesIUsedIFreeIUse%Mountedon/dev/mapper/vg_linuxbase-lv_root1806896151912428777285%/FilesystemInodesIUsedIFreeIUse%Mountedon/dev/mapper/vg_linuxbase-lv_root1806896151901528788185%/FilesystemInodesIUsedIFreeIUse%Mountedon/dev/mapper/vg_linuxbase-lv_root1806896151388029301684%/FilesystemInodesIUsedIFreeIUse%Mountedon/dev/mapper/vg_linuxbase-lv_root1806896151113229576484%/FilesystemInodesIUsedIFreeIUse%Mountedon/dev/mapper/vg_linuxbase-lv_root1806896150243430446284%/FilesystemInodesIUsedIFreeIUse%Mountedon/dev/mapper/vg_linuxbase-lv_root1806896149458331231383%/FilesystemInodesIUsedIFreeIUse%Mountedon/dev/mapper/vg_linuxbase-lv_root1806896148911131778583%/FilesystemInodesIUsedIFreeIUse%Mountedon/dev/mapper/vg_linuxbase-lv_root1806896148762931926783%/

#使用的rsync方法，观察Inodes释放速度：[oracle@jystdrac2~]$whiletrue;dodf-i/;sleep10;doneFilesystemInodesIUsedIFreeIUse%Mountedon/dev/mapper/vg_linuxbase-lv_root180689696302984386754%/FilesystemInodesIUsedIFreeIUse%Mountedon/dev/mapper/vg_linuxbase-lv_root180689695503785185953%/FilesystemInodesIUsedIFreeIUse%Mountedon/dev/mapper/vg_linuxbase-lv_root180689695308885380853%/FilesystemInodesIUsedIFreeIUse%Mountedon/dev/mapper/vg_linuxbase-lv_root180689695052385637353%/FilesystemInodesIUsedIFreeIUse%Mountedon/dev/mapper/vg_linuxbase-lv_root180689694875485814253%/FilesystemInodesIUsedIFreeIUse%Mountedon/dev/mapper/vg_linuxbase-lv_root180689694461386228353%/FilesystemInodesIUsedIFreeIUse%Mountedon/dev/mapper/vg_linuxbase-lv_root180689694261986427753%/FilesystemInodesIUsedIFreeIUse%Mountedon/dev/mapper/vg_linux