此列以/home分区为例。如果是根分区的数据被误删，这个恢复起来很麻烦，大概可以进单用户模式下只读方式挂载根分区，然后恢复。或者把整个硬盘取出来后，挂载到另外一台linux服务器上操作。
一、恢复ext4分区误删数据（亲自测试过，正常）
1、同步服务器时间。
[root@localhost ~]#yum install -y rdate [root@localhost ~]#rdate -s time-b.nist.gov [root@localhost ~]#clock -w
2、安装extundelete工具。
[root@localhost ~]#yum -y install e2fsprogs* gcc gcc-c++ gcc-g77 [root@localhost ~]#wget http://nchc.dl.sourceforge.net/project/extundelete/extundelete/0.2.4/extundelete-0.2.4.tar.bz2 [root@localhost ~]#tar -jxvf extundelete-0.2.4.tar.bz2 [root@localhost ~]#cd extundelete-0.2.4 [root@localhost ~]#./configure --prefix=/usr/local/extundelete [root@localhost ~]#make && make install [root@localhost ~]#/usr/local/extundelete/bin/extundelete --help
3、模拟误删除数据
[root@localhost ~]# rm -rf /home/netdisk 误删除
4、建议先停止一些频繁读写磁盘的服务。
[root@localhost ~]# for i in `chkconfig --list |grep kkmail|awk '{print $1}'`;do /etc/init.d/$i stop;done
5、恢复操作。
（1）卸载/home分区
[root@localhost ~]# fuser -k /home [root@localhost ~]# umount /home/
[root@localhost ~]# /usr/local/extundelete/bin/extundelete --inode 2 /dev/mapper/VolGroup-lv_home NOTICE: Extended attributes are not restored. Loading filesystem metadata ... 45 groups loaded. Group: 0 Contents of inode 2: 0000 | ed 41 00 00 00 10 00 00 d5 21 9e 5a 3f 24 9e 5a | .A.......!.Z?$.Z 0010 | 3f 24 9e 5a 00 00 00 00 00 00 03 00 08 00 00 00 | ?$.Z............ 0020 | 00 00 00 00 02 00 00 00 68 21 00 00 00 00 00 00 | ........h!...... 0030 | 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 | ................ 0040 | 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 | ................ 0050 | 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 | ................ 0060 | 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 | ................ 0070 | 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 | ................ 0080 | 1c 00 00 00 61 01 9b 61 01 9b 68 7f 3e 58 | ....da..da..h.>X 0090 | 38 15 9e 5a 00 00 00 00 00 00 00 00 00 00 02 ea | 8..Z............ 00a0 | 07 06 3c 00 00 00 00 00 21 00 00 00 00 00 00 00 | ..<.....!....... 00b0 | 73 65 6c 69 6e 75 78 00 00 00 00 00 00 00 00 00 | selinux......... 00c0 | 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 | ................ 00d0 | 00 00 00 00 00 00 00 00 00 00 00 00 73 79 73 74 | ............syst 00e0 | 65 6d 5f 75 3a 6f 62 6a 65 63 74 5f 72 3a 68 6f | em_u:object_r:ho 00f0 | 6d 65 5f 72 6f 6f 74 5f 74 3a 73 30 00 00 00 00 | me_root_t:s0.... Inode is Allocated File mode: 16877 Low 16 bits of Owner Uid: 0 Size in bytes: 4096 Access time: 15203127 Creation time: 1520313407 Modification time: 1520313407 Deletion Time: 0 Low 16 bits of Group Id: 0 Links count: 3 Blocks count: 8 File flags: 0 File version (for NFS): 0 File ACL: 0 Directory ACL: 0 Fragment address: 0 Direct blocks: 8552, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 Indirect block: 0 Double indirect block: 0 Triple indirect block: 0 File name | Inode number | Deleted status . 2 .. 2 lost+found 11 netdisk 130561 Deleted
备注：注意看Deleted。
（3）恢复数据
[root@localhost ~]# /usr/local/extundelete/bin/extundelete --restore-all /dev/mapper/VolGroup-lv_home # --restore-all是全部恢复 ，默认全将恢复出来的文件放在当前路径 RECOVERED_FILES/ 目录下，文件名为 file.I节点号 [root@localhost ~]# /usr/local/extundelete/bin/extundelete --restore-file 文件名 /dev/mapper/VolGroup-lv_home [root@localhost ~]# /usr/local/extundelete/bin/extundelete --restore-inode 12 /dev/mapper/VolGroup-lv_home
备注：恢复指定的时间点后被删文件
1).指定一个时间点
# date -d "Sep 4 03:09:13 2013" +%s
------------------
1378235353
------------------
2).恢复这个时间点后的文件
# /usr/local/extundelete/bin/extundelete --restore-all --after “1378235353” /dev/mapper/VolGroup-lv_home
--------------------
..........
--------------------
注:如果要恢之前的就用before参数。extundelete命令与after结合使用，在进行恢复时非常有用，可以过滤掉那太旧的文件，减小恢复压力。
6、重新挂载/home分区，并恢复数据，启动服务。
备注：还有这个恢复工具ext4magic也可以。
官方这样描述,如果您已经在ext4的文件系统中删除了文件,选extundelete是一个不错的选择,它能够恢复已删除文件的文件名及内容.
二、恢复ext3分区误删数据（没测试过，网上教程）
上面介绍的是在ext4文件格式下的文件删除后的恢复，那如果是ext3文件格式下的文件删除后想恢复，怎么办呢？
可以使用debugfs工具，这是linux系统自带工具，debugfs恢复Ext3的文件系统中被rm、rm -f 掉的文件。
[root@slave-node ~]# df -T Filesystem Type 1K-blocks Used Available Use% Mounted on /dev/sda3 ext3 1511708 2370036 141139672 2% / tmpfs tmpfs 32960412 0 32960412 0% /dev/shm /dev/sda1 ext3 198337 26798 161299 15% /boot
创建一个文件
[root@slave-node ~]# mkdir test [root@slave-node ~]# echo "123456" > /root/test/test.file
删除文件
[root@slave-node ~]# rm -rf /root/test/test.file
接着运用系统自带工具debugfs来恢复已删除的文件
首先打开，刚刚被删除文件所在的分区
注意上面显示的有<>尖括号内的数字就是我们要找的文件Inode号，执行logdump –i <8654024>
[root@slave-node ~]# debugfs debugfs 1.41.12 (17-May-2010) debugfs: open /dev/sda3 debugfs: ls -d /root/test 8654023 (12) . 8519681 (4084) .. <8654024> (4072) test.file debugfs: logdump -i 8654024 FS block 1006 logged at sequence 404351, journal block 7241 (inode block for inode 15): Inode: 15 Type: regular Mode: 06 Flags: 0×0 Generation: 0 User: 0 Group: 0 Size: 20 File ACL: 0 Directory ACL: 0 Links: 1 Blockcount: 8 Fragment: Address: 0 Number: 0 Size: 0 ctime: 0×48159f2d — Mon Apr 28 15:25:57 2008 atime: 0×48159f27 — Mon Apr 28 15:25:51 2008 mtime: 0×4806f070 — Thu Apr 17 12:08:40 2008 Blocks: (0+1): 102348 No magic number at block 7247: end of journal.
执行完命令后，显示了一屏信息，需要注意的是下面Blocks这一行后面的值（如上信息，需要记住Blocks这一行后面的数字102348）
输入quit，退出debugfs
debugfs: quit
[root@slave-node ~]#
执行如下命令进行恢复：
[root@slave-node ~]# dd if=/dev/sda3 of=/tmp/test.file.bk bs=4096 count=1 skip=102348 1+0 records in 1+0 records out 4096 bytes (4.1 kB) copied, 0.0110028 s, 372 kB/s
[root@slave-node ~]# cd /tmp/ [root@slave-node tmp]# cat test.file.bk [root@slave-node tmp]# mv test.file.bk /root/test.file [root@slave-node tmp]# cat /root/test.file 123456
备注：还有这个恢复工具ext3grep。
如果是在ext3的文件系统中删除了文件,extundelete和ext3grep比较仍然有一些优点,extundelete分析日志文件后,能够立即恢复一个文件,ext3grep分析整个硬盘才开始恢复硬盘中的文件,ext3grep方法是是有效的从一个小分区恢复多个文件,所以相比而言,如果需要从一个大的分区中恢复文件,extundelete要快些.
三、恢复xfs分区误删数据
xfs用xfs_irecover工具恢复。
http://www.ufsexplorer.com/rdr_xfs.php
以下摘自官网。
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Q: Does the filesystem have an undelete capability?
There is no undelete in XFS.
However, if an inode is unlinked but neither it nor its associated data blocks get immediately re-used and overwritten, there is some small chance to recover the file from the disk.
photorec, xfs_irecover or xfsr are some tools which attempt to do this, with varying success.
There are also commercial data recovery services and closed source software like Raise Data Recovery for XFS which claims to recover data, although this has not been tested by the XFS developers.
As always, the best advice is to keep good backups.
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