Admin X

gzip解壓縮
1.先將檔名改為.gz
 mv initrd-2.6.18-92.el5.img initrd-2.6.18-92.el5.gz
2.gzip -d       # -d --decompress 
 gzip -d initrd-2.6.18-92.el5.gz

file initrd-2.6.18-92.el5
initrd-2.6.18-92.el5: ASCII cpio archive (SVR4 with no CRC)

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cpio 解壓縮
cpio -ivcdu < initrd-2.6.18-92.el5

cpio - copy files to and from archives

‘-c’   Identical  to “-H newc”, use the new (SVR4) portable format.  
    If  you wish the old portable (ASCII) archive format, use  
                “-H  odc” instead.

‘-d, --make-directories’
             Create leading directories where needed.

‘-i, --extract’
              Run in copy-in mode.  see “Copy-in mode”.

‘-u, --unconditional’
              Replace  all  files,  without asking whether to replace existing
              newer files with older files.

‘-v, --verbose’冗長的
              List the files processed, or with ‘-t’, give an  ‘ls  -l’  style
              table  of contents listing.  In a verbose table of contents of a
              ustar archive, user and group names in the archive that  do  not
              exist  on the local system are replaced by the names that corre-
              spond locally to the numeric UID and GID stored in the  archive.

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查看硬碟使用容量

# df -Th

Filesystem                           Type         Size  Used     Avail   Use%  Mounted on

/dev/mapper/centos-root       xfs          6.7G   4.6G    2.1G    69%    /

devtmpfs                          devtmpfs     906M     0     906M     0%    /dev

tmpfs                                   tmpfs       921M   88K   920M     1%     /dev/shm

tmpfs                                   tmpfs       921M  8.7M   912M    1%     /run

tmpfs                                    tmpfs      921M     0      921M    0%     /sys/fs/cgroup

/dev/sda1                                xfs       497M  157M  341M    32%    /boot

tmpfs                                    tmpfs     185M   8.0K    184M    1%    /run/user/0

-h, --  human-readable (自動選擇KB,MB,GB顯示)    
          print sizes in human readable format (e.g., 1K 234M 2G)/

-T, --   print file system Type

列出目錄使用的容量
# du -sh /*
 -s, --summarize
   display only a total for each argument

0             /bin
131M      /boot
816K      /dev
39M       /etc
5.7M      /home
0           /lib
0           /lib64
0           /media
0          /mnt
20M     /opt
du: cannot access ‘/proc/4761/task/4761/fd/4’: No such file or directory
du: cannot access ‘/proc/4761/task/4761/fdinfo/4’: No such file or directory
du: cannot access ‘/proc/4761/fd/4’: No such file or directory
du: cannot access ‘/proc/4761/fdinfo/4’: No such file or directory
0            /proc
5.3M     /root
8.8M     /run
0           /sbin
0           /srv
0           /sys
216K     /tmp
3.3G     /usr
1.3G     /var

====================================================

用hdparm 測試讀取速度

 -t   Perform device read timings

 -T   Perform cache read timings

[root@localhost ~]# hdparm -t /dev/sda

/dev/sda:

 Timing buffered disk reads: 612 MB in  3.00 seconds = 203.94 MB/sec

[root@localhost ~]# hdparm -t --direct /dev/sda

/dev/sda:

 Timing O_DIRECT disk reads: 684 MB in  3.04 seconds = 225.30 MB/sec

[root@localhost ~]# hdparm -T /dev/sda

/dev/sda:

 Timing cached reads:   9900 MB in  2.00 seconds = 4954.13 MB/sec

[root@localhost ~]# hdparm -T --direct /dev/sda

/dev/sda:

 Timing O_DIRECT cached reads:   102 MB in  2.03 seconds =  50.33 MB/sec

====================================================

查看記憶體指令 — free

free 指令可以看實體記憶體和 Swap 的使用情況

-h human readable output (automatic unit scaling)

-s update every [delay] seconds

[root@localhost ~]# free -hs 5
[root@localhost ~]# watch -n 5 'free -h'  (比較清楚)

             total       used       free     shared    buffers     cached

Mem:          996M       366M       629M       3.6M       8.3M        65M

-/+ buffers/cache:       292M       703M

Swap:         815M         0B       815M

====================================================

RAM Disk

[root@localhost ~]# mkdir /tmp/tmpfs

[root@localhost ~]# mount -t tmpfs -o size=50M tmpfs /tmp/tmpfs/

-t, --types vfstype

-o, --options opts

# df -TH

Filesystem           Type    Size  Used Avail Use% Mounted on

/dev/mapper/VolGroup-lv_root

                     ext4    7.0G  4.3G  2.4G  64% /

tmpfs                tmpfs   523M  308k  523M   1% /dev/shm

/dev/sda1            ext4    500M   39M  435M   9% /boot

tmpfs                tmpfs    53M     0   53M   0% /tmp/tmpfs

寫入測試

# dd count=50 bs=1M if=/dev/zero of=/tmp/tmpfs/test.img

50+0 records in

50+0 records out

52428800 bytes (52 MB) copied, 0.0617388 s, 849 MB/s

# dd count=12500 bs=4k if=/dev/zero of=/tmp/tmpfs/test.img

12500+0 records in

12500+0 records out

51200000 bytes (51 MB) copied, 0.0744877 s, 687 MB/s

dd count=2k bs=1M if=/tmp/ramdisk/test2g.img of=/dev/null

讀取測試

# dd count=50 bs=1M if=/tmp/tmpfs/test.img of=/dev/null

48+1 records in

48+1 records out

51200000 bytes (51 MB) copied, 0.0272163 s, 1.9 GB/s

# dd count=12500 bs=4k if=/tmp/tmpfs/test2g.img of=/dev/null

12500+0 records in

12500+0 records out

51200000 bytes (51 MB) copied, 0.030945 s, 1.7 GB/s

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