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在Linux中刪除超大(100-200GB)文件的實現(xiàn)方式

 更新時間:2024年04月11日 09:57:50   作者:CN-FuWei  
這篇文章主要介紹了在Linux中刪除超大(100-200GB)文件的實現(xiàn)方式,具有很好的參考價值,希望對大家有所幫助,如有錯誤或未考慮完全的地方,望不吝賜教

一、IO調(diào)度策略

1.1、idle

空閑磁盤調(diào)度;

該調(diào)度策略是在當前系統(tǒng)沒有其他進程需要進行磁盤IO時,才能進行磁盤;

因此該策略對當前系統(tǒng)的影響基本為0;

當然,該調(diào)度策略不能帶有任何優(yōu)先級參數(shù);

1.2、Best effort

是缺省的磁盤IO調(diào)度策略;   

(1)該調(diào)度策略可以指定優(yōu)先級參數(shù)(范圍是0~7,數(shù)值越小,優(yōu)先級越高);   

(2)針對處于同一優(yōu)先級的程序?qū)⒉蓃ound-robin方式;   

(3)對于best effort調(diào)度策略,8個優(yōu)先級等級可以說明在給定的一個調(diào)度窗口中時間片的大??;   

(4)目前,普調(diào)用戶(非root用戶)是可以使用該調(diào)度策略;   

(5)在內(nèi)核2.6.26之前,沒有設(shè)置IO優(yōu)先級的進程會使用“none”作為調(diào)度策略,但是這種策略使得進程看起來像是采用了best effort調(diào)度策略,因為其優(yōu)先級是通過關(guān)于   cpu nice有關(guān)的公式計算得到的:io_priority = (cpu_nice + 20) /5   

(6)在內(nèi)核2.6.26之后,如果當前系統(tǒng)使用的是CFQ調(diào)度器,那么如果進程沒有設(shè)置IO優(yōu)先級級別,將采用與內(nèi)核2.6.26之前版本同樣的方式,推到出io優(yōu)先級級別;

1.3、Real time

實時調(diào)度策略,如果設(shè)置了該磁盤IO調(diào)度策略,則立即訪問磁盤,不管系統(tǒng)中其他進程是否有IO。

因此使用實時調(diào)度策略,需要注意的是,該訪問策略可能會使得其他進程處于等待狀態(tài);

二、ionice命令-設(shè)置排程優(yōu)先級

2.1、安裝

[root@docker][19:43:12][OK] ~ 
#yum provides */ionice
Loaded plugins: fastestmirror
Loading mirror speeds from cached hostfile
 * base: mirrors.aliyun.com
 * epel: mirror.01link.hk
 * extras: mirrors.aliyun.com
 * updates: mirrors.aliyun.com
epel/x86_64/filelists_db                                                                                                     |  12 MB  00:00:08     
extras/7/x86_64/filelists_db                                                                                                 | 276 kB  00:00:01     
updates/7/x86_64/filelists_db                                                                                                |  10 MB  00:00:42     
util-linux-2.23.2-65.el7.i686 : A collection of basic system utilities
Repo        : base
Matched from:
Filename    : /usr/bin/ionice
Filename    : /usr/share/bash-completion/completions/ionice
 
 
 
util-linux-2.23.2-65.el7.x86_64 : A collection of basic system utilities
Repo        : base
Matched from:
Filename    : /usr/bin/ionice
Filename    : /usr/share/bash-completion/completions/ionice
 
 
 
util-linux-2.23.2-65.el7_9.1.i686 : A collection of basic system utilities
Repo        : updates
Matched from:
Filename    : /usr/bin/ionice
Filename    : /usr/share/bash-completion/completions/ionice
 
 
 
util-linux-2.23.2-65.el7_9.1.x86_64 : A collection of basic system utilities
Repo        : updates
Matched from:
Filename    : /usr/bin/ionice
Filename    : /usr/share/bash-completion/completions/ionice
 
 
 
util-linux-2.23.2-65.el7.x86_64 : A collection of basic system utilities
Repo        : @anaconda
Matched from:
Filename    : /usr/bin/ionice
Filename    : /usr/share/bash-completion/completions/ionice

安裝

yum install util-linux-2.23.2-65.el7_9.1.x86_64 -y

2.2、用法

[root@docker][19:35:01][OK] ~ 
#ionice --help
 
ionice - sets or gets process io scheduling class and priority.
 
Usage:
  ionice [OPTION] -p PID [PID...]
  ionice [OPTION] COMMAND
 
Options:
  -c, --class <class>   scheduling class name or number
                           0: none, 1: realtime, 2: best-effort, 3: idle
  -n, --classdata <num> scheduling class data
                           0-7 for realtime and best-effort classes
  -p, --pid=PID         view or modify already running process
  -t, --ignore          ignore failures
  -V, --version         output version information and exit
  -h, --help            display this help and exit

2.3、示例

—- Deleting Huge Files in Linux —–
# ionice -c 3 rm /var/logs/syslog
# ionice -c 3 rm -rf /var/log/apache

注意:要使用安全的方法刪除大檔案,我們可以使 shred、wipe 以及 secure-deletion 工具包中的不同工具,而不是 rm 命令。

三、Shred -覆蓋文件以隱藏內(nèi)容

3.1、安裝軟件包

yum install coreutils-8.22-24.el7_9.2.x86_64 -y

3.2、命令及參數(shù)選項

[root@192_168_209_128 ~]# shred --help
Usage: shred [OPTION]... FILE...
Overwrite the specified FILE(s) repeatedly, in order to make it harder
for even very expensive hardware probing to recover the data.
Mandatory arguments to long options are mandatory for short options too.
  -f, --force    change permissions to allow writing if necessary
  -n, --iterations=N  overwrite N times instead of the default (3)
      --random-source=FILE  get random bytes from FILE
  -s, --size=N   shred this many bytes (suffixes like K, M, G accepted)
  -u, --remove[=HOW]  truncate and remove file after overwriting; See below
  -v, --verbose  show progress
  -x, --exact    do not round file sizes up to the next full block;
                   this is the default for non-regular files
  -z, --zero     add a final overwrite with zeros to hide shredding
      --help     display this help and exit
      --version  output version information and exit

選項說明:

  • -z- 添加一個帶有零的最終覆蓋以隱藏切碎。
  • -v– 可以顯示操作進度。
  • -u- 覆蓋后截斷和刪除文件。
  • -n– 指定覆蓋文件內(nèi)容的次數(shù)(默認為 3)。

3.3、示例

shred覆蓋文件以隱藏其內(nèi)容,也可以選擇刪除它。

[root@docker][19:51:03][OK] ~ 
#shred -zvu -n 5 cuttingLog_bak 
shred: cuttingLog_bak: pass 1/6 (random)...
shred: cuttingLog_bak: pass 2/6 (ffffff)...
shred: cuttingLog_bak: pass 3/6 (random)...
shred: cuttingLog_bak: pass 4/6 (000000)...
shred: cuttingLog_bak: pass 5/6 (random)...
shred: cuttingLog_bak: pass 6/6 (000000)...
shred: cuttingLog_bak: removing
shred: cuttingLog_bak: renamed to 00000000000000
shred: 00000000000000: renamed to 0000000000000
shred: 0000000000000: renamed to 000000000000
shred: 000000000000: renamed to 00000000000
shred: 00000000000: renamed to 0000000000
shred: 0000000000: renamed to 000000000
shred: 000000000: renamed to 00000000
shred: 00000000: renamed to 0000000
shred: 0000000: renamed to 000000
shred: 000000: renamed to 00000
shred: 00000: renamed to 0000
shred: 0000: renamed to 000
shred: 000: renamed to 00
shred: 00: renamed to 0
shred: cuttingLog_bak: removed

四、Wipe —在 Linux 中安全擦除文件

介紹:Linux wipe命令可以安全地從磁存儲器中擦除文件,從而無法恢復(fù)。

4.1、安裝軟件包

rpm -ivh wipe-2.2.0-1.2.el7.rf.x86_64.rpm

4.2、命令及參數(shù)選項

[root@docker][19:58:11][OK] ~ 
#wipe -h
Wipe v2.2.0 - released January 10, 2004
by Tom Vier <nester@users.sf.net>
 
Usage is wipe [options] [file-list]
 
Options:         Default: wipe -ZdntVAkO -S512 -C4096 -l1 -x8 -p1
 
-h          --   help - display this screen
-u          --   usage
-c          --   show copyright and license
-w          --   show warranty information
-i  and  -I --   enable (-i) or disable (-I) interaction - overrides force
-f          --   force file wiping and override interaction
-r  and  -R --   recursion - traverse subdirectories
-s          --   silent - disable percentage and error reporting
-v          --   force verbose - always show percentage
-V          --   verbose - show percentage if file is >= 25K
-d  and  -D --   delete (-d) or keep (-D) after wiping
-n  and  -N --   delete (-n) or skip (-N) special files
-k  and  -K --   lock (-k) or don't lock (-K) files
-z          --   zero-out file - single pass of zeroes
-Z          --   perform normal wipe passes
-t  and  -T --   enable (-t) or disable (-T) static passes
-a  and  -A --   write until out of space (-a) or don't (-A)
-o[size] -O --   write to stdout (-o) or use files (-O)
-B(count)   --   block device sector count
-S(size)    --   block device sector size - default 512 bytes
                 or stdout write length when used with -A
-C(size)    --   chunk size - maximum file buffer size in kilobytes (2^10)
-l[0-2]     --   sets wipe secure level
-x[1-32] -X --   sets number of random passes per wipe or disables
-p(1-32)    --   wipe file x number of times
-b(0-255)   --   overwrite file with this value byte

4.3、示例

[root@docker][19:59:50][OK] ~ 
#wipe -fi cuttingLog_bak 
wipe: destroy file `cuttingLog_bak'? y

五、Linux 安全刪除工具包

Secure-delete是一個安全文件刪除工具的集合,其中包含srm (secure_deletion) 工具,用于安全刪除文件。

5.1、安裝軟件包

yum -y install srm-1.2.15-1.el7.x86_64

5.2、命令及參數(shù)選項

[root@docker][20:05:39][OK] ~ 
#srm --help
Usage: srm [OPTION]... [FILE]...
Overwrite and remove (unlink) the files. By default use the 35-pass Gutmann
method to overwrite files.
 
  -d, --directory       ignored (for compatability with rm(1))
  -f, --force           ignore nonexistant files, never prompt
  -i, --interactive     prompt before any removal
  -x, --one-file-system do not cross file system boundaries
  -s, --simple          overwrite with single pass using 0x00 (default)
  -P, --openbsd         overwrite with three passes like OpenBSD rm
  -D, --dod             overwrite with 7 US DoD compliant passes
  -E, --doe             overwrite with 3 US DoE compliant passes
  -G, --gutmann         overwrite with 35-pass Gutmann method
  -C, --rcmp            overwrite with Royal Canadian Mounted Police passes
  -r, -R, --recursive   remove the contents of directories
  -v, --verbose         explain what is being done
  -h, --help            display this help and exit
  -V, --version         display version information and exit

5.3、示例

#srm -vf cuttingLog_bal 
srm: removing cuttingLog_bal

總結(jié)

以上為個人經(jīng)驗,希望能給大家一個參考,也希望大家多多支持腳本之家。

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