发现如果人品不好做试验都是问题很多,晚上又把fstab给写错了,导致系统不能起来,因为当时处理该故障未截图,后续在网上找了几张图片,大体说明处理思路
系统启动报 filesystems 失败,输入root密码进入repair filesystem模式

尝试修改 /etc/fstab 发现系统是read-only模式

重新mount -n -o remount,rw /重新mount文件系统

重新修改/etc/fstab,除掉错误记录,然后使用init 6/reboot命令重启系统

今天群中有个朋友的客户闲着没事rm掉了数据文件,然后讨论到使用extundelete进行了恢复,抢救了部分未被覆盖的数据文件。该软件官方地址:http://extundelete.sourceforge.net/
安装extundelete

[root@xifenfei tmp]# bunzip2 extundelete-0.2.0.tar.bz2
[root@xifenfei tmp]# tar xvf extundelete-0.2.0.tar
extundelete-0.2.0/
extundelete-0.2.0/README
extundelete-0.2.0/acinclude.m4
extundelete-0.2.0/configure.ac
extundelete-0.2.0/aclocal.m4
extundelete-0.2.0/Makefile.am
extundelete-0.2.0/Makefile.in
extundelete-0.2.0/config.h.in
extundelete-0.2.0/configure
extundelete-0.2.0/compile
extundelete-0.2.0/depcomp
extundelete-0.2.0/install-sh
extundelete-0.2.0/missing
extundelete-0.2.0/LICENSE
extundelete-0.2.0/autogen.sh
extundelete-0.2.0/src/
extundelete-0.2.0/src/Makefile.am
extundelete-0.2.0/src/Makefile.in
extundelete-0.2.0/src/extundelete.cc
extundelete-0.2.0/src/block.c
extundelete-0.2.0/src/insertionops.cc
extundelete-0.2.0/src/block.h
extundelete-0.2.0/src/extundelete.h
extundelete-0.2.0/src/extundelete-priv.h
extundelete-0.2.0/src/jfs_compat.h
extundelete-0.2.0/src/kernel-jbd.h
[root@xifenfei tmp]# cd extundelete-0.2.0
[root@xifenfei extundelete-0.2.0]#  ./configure
Configuring extundelete 0.2.0
Writing generated files to disk
[root@xifenfei extundelete-0.2.0]# make && make install
make -s all-recursive
Making all in src
Making install in src
  /usr/bin/install -c 'extundelete' '/usr/local/bin/extundelete'

恢复操作命令

--umount或者read only 分区(如果umount不成功,可以通过fuser -km /www类似方法找出来占用进程）
 umount /dev/partition
 mount -o remount,ro /dev/partition
--恢复文件
extundelete /dev/partition --restore-all
extundelete /dev/partition --restore-directory /backup/gnutool-delete
extundelete /dev/partition --restore-files /etc/passwd

测试恢复

--基于目录恢复
[root@xifenfei tmp]#extundelete /dev/sdb1  --restore-directory /u01/xifenfei
Loading filesystem metadata ... 160 groups loaded.
Loading journal descriptors ... 23 descriptors loaded.
Writing output to directory RECOVERED_FILES/
Failed to restore file /u01/xifenfei
Could not find correct inode number past inode 2.
[root@xifenfei tmp]# cd RECOVERED_FILES/
[root@xifenfei RECOVERED_FILES]# ll
total 0
--未成功
--基于磁盘恢复
[root@xifenfei RECOVERED_FILES]#extundelete /dev/sdb1  --restore-all
Loading filesystem metadata ... 160 groups loaded.
Loading journal descriptors ... 23 descriptors loaded.
Writing output to directory RECOVERED_FILES/
Searching for recoverable inodes in directory / ...
4 recoverable inodes found.
Looking through the directory structure for deleted files ...
Failed to restore inode 1966081 to file RECOVERED_FILES/xifenfei:Inode does not correspond to a regular file.
Restored inode 1966082 to file RECOVERED_FILES/xifenfei/xff.txt
Failed to restore inode 1966083 to file RECOVERED_FILES/xifenfei/xff:Inode does not correspond to a regular file.
Restored inode 1966084 to file RECOVERED_FILES/xifenfei/xff/xff.txt132
0 recoverable inodes still lost.
[root@xifenfei RECOVERED_FILES]# ll
total 4
drwxr-xr-x 3 root root 4096 Aug 31 21:36 RECOVERED_FILES
[root@xifenfei RECOVERED_FILES]# cd RECOVERED_FILES/
[root@xifenfei RECOVERED_FILES]# ll
total 4
drwxr-xr-x 3 root root 4096 Aug 31 21:36 xifenfei
[root@xifenfei RECOVERED_FILES]# cd xifenfei/
[root@xifenfei xifenfei]# ll
total 20
drwxr-xr-x 2 root root  4096 Aug 31 21:36 xff
-rw-r--r-- 1 root root 13231 Aug 31 21:36 xff.txt
[root@xifenfei xifenfei]# cd xff
[root@xifenfei xff]# ll
total 16
-rw-r--r-- 1 root root 13231 Aug 31 21:36 xff.txt132
--恢复成功
--基于文件恢复
[root@xifenfei xff]# extundelete /dev/sdb1  --restore-files /u01/xifenfei/xff.txt
Loading filesystem metadata ... 160 groups loaded.
Loading journal descriptors ... 23 descriptors loaded.
Writing output to directory RECOVERED_FILES/
[root@xifenfei xff]# cd RECOVERED_FILES/
[root@xifenfei RECOVERED_FILES]# ll
total 0
--未成功

通过上述实验证明extundelete还是有很大的不完整性,基于整个磁盘的恢复功能较为强大,基于目录和文件的恢复还不够强大.不过该软件在很多时候还是有救火的功能,特别是当蛋筒的人员删除了数据库的部分文件之时.

当前包含磁盘

[root@xifenfei ~]# fdisk -l
Disk /dev/sda: 21.4 GB, 21474836480 bytes
255 heads, 63 sectors/track, 2610 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
   Device Boot      Start         End      Blocks   Id  System
/dev/sda1   *           1        2355    18916506   83  Linux
/dev/sda2            2356        2610     2048287+  82  Linux swap / Solaris
Disk /dev/sdb: 21.4 GB, 21474836480 bytes
255 heads, 63 sectors/track, 2610 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
   Device Boot      Start         End      Blocks   Id  System
/dev/sdb1               1        2610    20964793+  83  Linux
Disk /dev/sdc: 2147 MB, 2147483648 bytes
255 heads, 63 sectors/track, 261 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk /dev/sdc doesn't contain a valid partition table
Disk /dev/sdd: 21.4 GB, 21474836480 bytes
255 heads, 63 sectors/track, 2610 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
   Device Boot      Start         End      Blocks   Id  System
/dev/sdd1               1         100      803218+  83  Linux
/dev/sdd2             101        1000     7229250   83  Linux

查看iscsi运行情况

[root@xifenfei ~]# rpm -aq|grep iscsi
iscsi-initiator-utils-6.2.0.872-10.0.1.el5
[root@xifenfei ~]#  chkconfig --list |grep iscsi
iscsi           0:off   1:off   2:on    3:on    4:on    5:on    6:off
iscsid          0:off   1:off   2:off   3:on    4:on    5:on    6:off
[root@xifenfei ~]# ps -ef|grep iscs
root      2753     2  0 Jun21 ?        00:00:00 [iscsi_eh]
root     15793     1  0 09:08 ?        00:00:00 brcm_iscsiuio
root     15800     1  0 09:08 ?        00:00:00 iscsid
root     15802     1  0 09:08 ?        00:00:00 iscsid
root     19533 15269  0 10:11 pts/1    00:00:00 grep iscs

配置iscsi存储

[root@xifenfei ~]# iscsiadm -m discovery -t sendtargets -p 192.168.1.254:3260
192.168.1.254:3260,1 iqn.2006-01.com.openfiler:tsn.32b32087937b
[root@xifenfei ~]# iscsiadm -m node –T iqn.2006-01.com.openfiler:tsn.32b32087937b -p 192.168.1.254:3260 -l
Logging in to [iface: default, target: iqn.2006-01.com.openfiler:tsn.32b32087937b, portal: 192.168.1.254,3260]
Login to [iface: default, target: iqn.2006-01.com.openfiler:tsn.32b32087937b, portal: 192.168.1.254,3260] successful.
[root@xifenfei ~]# iscsiadm -m node –T iqn.2006-01.com.openfiler:tsn.32b32087937b -p 192.168.1.254:3260
>--op update -n node.startup -v automatic

当前包含磁盘

[root@xifenfei ~]# fdisk -l
Disk /dev/sda: 21.4 GB, 21474836480 bytes
255 heads, 63 sectors/track, 2610 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
   Device Boot      Start         End      Blocks   Id  System
/dev/sda1   *           1        2355    18916506   83  Linux
/dev/sda2            2356        2610     2048287+  82  Linux swap / Solaris
Disk /dev/sdb: 21.4 GB, 21474836480 bytes
255 heads, 63 sectors/track, 2610 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
   Device Boot      Start         End      Blocks   Id  System
/dev/sdb1               1        2610    20964793+  83  Linux
Disk /dev/sdc: 2147 MB, 2147483648 bytes
255 heads, 63 sectors/track, 261 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk /dev/sdc doesn't contain a valid partition table
Disk /dev/sdd: 21.4 GB, 21474836480 bytes
255 heads, 63 sectors/track, 2610 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
   Device Boot      Start         End      Blocks   Id  System
/dev/sdd1               1         100      803218+  83  Linux
/dev/sdd2             101        1000     7229250   83  Linux
Disk /dev/sde: 1073 MB, 1073741824 bytes
34 heads, 61 sectors/track, 1011 cylinders
Units = cylinders of 2074 * 512 = 1061888 bytes
Disk /dev/sde doesn't contain a valid partition table
Disk /dev/sdf: 1073 MB, 1073741824 bytes
34 heads, 61 sectors/track, 1011 cylinders
Units = cylinders of 2074 * 512 = 1061888 bytes
Disk /dev/sdf doesn't contain a valid partition table
Disk /dev/sdg: 1073 MB, 1073741824 bytes
34 heads, 61 sectors/track, 1011 cylinders
Units = cylinders of 2074 * 512 = 1061888 bytes
Disk /dev/sdg doesn't contain a valid partition table

卸载iscsi存储

[root@xifenfei ~]# iscsiadm -m node --logoutall=all
Logging out of session [sid: 3, target: iqn.2006-01.com.openfiler:tsn.32b32087937b, portal: 192.168.1.254,3260]
Logout of [sid: 3, target: iqn.2006-01.com.openfiler:tsn.32b32087937b, portal: 192.168.1.254,3260] successful.
[root@xifenfei ~]# iscsiadm -m node --op delete --targetname iqn.2006-01.com.openfiler:tsn.32b32087937b

当前包含磁盘

[root@xifenfei ~]# fdisk -l
Disk /dev/sda: 21.4 GB, 21474836480 bytes
255 heads, 63 sectors/track, 2610 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
   Device Boot      Start         End      Blocks   Id  System
/dev/sda1   *           1        2355    18916506   83  Linux
/dev/sda2            2356        2610     2048287+  82  Linux swap / Solaris
Disk /dev/sdb: 21.4 GB, 21474836480 bytes
255 heads, 63 sectors/track, 2610 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
   Device Boot      Start         End      Blocks   Id  System
/dev/sdb1               1        2610    20964793+  83  Linux
Disk /dev/sdc: 2147 MB, 2147483648 bytes
255 heads, 63 sectors/track, 261 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk /dev/sdc doesn't contain a valid partition table
Disk /dev/sdd: 21.4 GB, 21474836480 bytes
255 heads, 63 sectors/track, 2610 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
   Device Boot      Start         End      Blocks   Id  System
/dev/sdd1               1         100      803218+  83  Linux
/dev/sdd2             101        1000     7229250   83  Linux

iscsi操作总结

增加iscsi存储
(1)发现iscsi存储:iscsiadm -m discovery -t st -p ISCSI_IP
(2)查看iscsi发现记录:iscsiadm -m node
(3)登录iscsi存储:iscsiadm -m node -T LUN_NAME -p ISCSI_IP -l
(4)开机自动: iscsiadm -m node –T LUN_NAME -p ISCSI_IP --op update -n node.startup -v automatic
删除iscsi存储
(1)登出iscsi存储 iscsiadm -m node -T LUN_NAME -p ISCSI_IP -u
(2)对出iscsi所有登录 iscsiadm -m node --logoutall=all
(3)删除iscsi发现记录:iscsiadm -m node -o delete -T LUN_NAME -p ISCSI_IP
登入需验证码的节点
(1)开启认证
iscsiadm -m node -T LUN_NAME -o update --name node.session.auth.authmethod --value=CHAP
*.使用-o同--op
(2)添加用户
iscsiadm -m node -T LUN_NAME --op update --name node.session.auth.username --value=[用户名]
(3)添加密码
iscsiadm –m node –T LUN_NAME –op update –name node.session.auth.password –value=[密码]

很多时候，我们的脚本中涉及的用户名/密码/ip等敏感信息，我们需要使用一些加密方面来屏蔽这些信息，确保我们的系统安全(主要防菜鸟)，虽然shc可以实现强大的加密功能，但是他需要另外安装shc软件，比较麻烦，应对一般的加密，个人推荐直接喜用系统自带的gzexe(大部分Linux，unix都有)

[root@xifenfei tmp]# more xifenfei.sh
#!/usr/bin/ksh
echo 'xifenfei--'`date`
[root@xifenfei tmp]# ./xifenfei.sh
xifenfei--Tue Mar 6 13:31:35 CST 2012
[root@xifenfei tmp]# ls -l xifenfei.sh
-rwxr-xr-x 1 root root 40 Mar  6 13:30 xifenfei.sh
--加密操作
[root@xifenfei tmp]# gzexe xifenfei.sh
xifenfei.sh:     -5.0%
[root@xifenfei tmp]# ls -l xifenfei.sh*
-rwxr-xr-x 1 root root 449 Mar  6 13:31 xifenfei.sh
-rwxr-xr-x 1 root root  40 Mar  6 13:30 xifenfei.sh~
--加密后文件内容
[root@xifenfei tmp]# strings xifenfei.sh
#!/bin/sh
skip=14
tmpdir=`/bin/mktemp -d ${TMPDIR:-/tmp}/gzexe.XXXXXXXXXX` || exit 1
prog="${tmpdir}/`echo \"$0\" | sed 's|^.*/||'`"
if /usr/bin/tail -n +$skip "$0" | "/bin"/gzip -cd > "$prog"; then
  /bin/chmod 700 "$prog"
  trap '/bin/rm -rf $tmpdir; exit $res' EXIT
  "$prog" ${1+"$@"}; res=$?
else
  echo "Cannot decompress $0"
  /bin/rm -rf $tmpdir
  exit 1
fi; exit $res
xifenfei.sh
UOHI,IM

这里的xifenfei.sh是加密后文件，xifenfei.sh~是源码文件(加密前文件)，只需要运行xifenfie.sh即可实现原脚本功能
优点:在大部分系统上均可运行，不用安装额外软件
缺点:破解容易,放君子不防小人