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创建ext4文件系统
[root@localhost ~]# mkfs.ext4 /dev/sdb1
mke2fs 1.42.9 (28-Dec-2013)
Filesystem label=
OS type: Linux
Block size=4096 (log=2)
Fragment size=4096 (log=2)
Stride=0 blocks, Stripe width=0 blocks
1310720 inodes, 5242624 blocks
262131 blocks (5.00%) reserved for the super user
First data block=0
Maximum filesystem blocks=2153775104
160 block groups
32768 blocks per group, 32768 fragments per group
8192 inodes per group
Superblock backups stored on blocks:
32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208,
4096000
Allocating group tables: done
Writing inode tables: done
Creating journal (32768 blocks): done
Writing superblocks and filesystem accounting information: done
[root@localhost ~]# mkdir /sdb
[root@localhost ~]# mount /dev/sdb1 /sdb
[root@localhost ~]# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/ol-root 36G 4.0G 32G 12% /
devtmpfs 1.8G 0 1.8G 0% /dev
tmpfs 1.8G 0 1.8G 0% /dev/shm
tmpfs 1.8G 8.9M 1.8G 1% /run
tmpfs 1.8G 0 1.8G 0% /sys/fs/cgroup
/dev/sda1 497M 195M 303M 40% /boot
tmpfs 369M 0 369M 0% /run/user/0
/dev/sdb1 20G 45M 19G 1% /sdb
准备测试数据
[root@localhost sdb]# cd /etc/sysctl.d/ [root@localhost sysctl.d]# ls 99-sysctl.conf [root@localhost sysctl.d]# cp 99-sysctl.conf /sdb [root@localhost sysctl.d]# more 99-sysctl.conf # System default settings live in /usr/lib/sysctl.d/00-system.conf. # To override those settings, enter new settings here, or in an /etc/sysctl.d/<name>.conf file # # For more information, see sysctl.conf(5) and sysctl.d(5).
破坏ext4文件系统
[root@localhost ~]# dd if=/dev/zero of=/dev/sdb1 bs=1024 count=5 5+0 records in 5+0 records out 5120 bytes (5.1 kB) copied, 0.00270838 s, 1.9 MB/s [root@localhost ~]# mount /dev/sdb1 /sdb mount: unknown filesystem type '(null)'
日志报错
[ 8868.362628] sd 32:0:1:0: [sdb] Cache data unavailable [ 8868.362632] sd 32:0:1:0: [sdb] Assuming drive cache: write through [ 8868.363714] sdb: sdb1 [ 8868.390297] sd 32:0:1:0: [sdb] Cache data unavailable [ 8868.390301] sd 32:0:1:0: [sdb] Assuming drive cache: write through [ 8868.391462] sdb: sdb1 [ 8900.130143] EXT4-fs (sdb1): mounted filesystem with ordered data mode. Opts: (null) [ 8900.130163] SELinux: initialized (dev sdb1, type ext4), uses xattr [ 8902.803966] sdb1: WRITE SAME failed. Manually zeroing.
fsck修复
[root@localhost ~]# fsck -t ext4 /dev/sdb1 fsck from util-linux 2.23.2 e2fsck 1.42.9 (28-Dec-2013) ext2fs_open2: Bad magic number in super-block fsck.ext4: Superblock invalid, trying backup blocks... /dev/sdb1 was not cleanly unmounted, check forced. Pass 1: Checking inodes, blocks, and sizes Pass 2: Checking directory structure Pass 3: Checking directory connectivity Pass 4: Checking reference counts Pass 5: Checking group summary information Free blocks count wrong for group #1 (31740, counted=31739). Fix<y>? yes Free blocks count wrong (5116302, counted=5116301). Fix<y>? yes Free inodes count wrong for group #0 (8181, counted=8180). Fix<y>? yes Free inodes count wrong (1310709, counted=1310708). Fix<y>? yes /dev/sdb1: ***** FILE SYSTEM WAS MODIFIED ***** /dev/sdb1: 12/1310720 files (0.0% non-contiguous), 126323/5242624 blocks
测试修复结果
[root@localhost ~]# [root@localhost ~]# [root@localhost ~]# mount /dev/sdb1 /sdb [root@localhost ~]# df -h Filesystem Size Used Avail Use% Mounted on /dev/mapper/ol-root 36G 4.0G 32G 12% / devtmpfs 1.8G 0 1.8G 0% /dev tmpfs 1.8G 0 1.8G 0% /dev/shm tmpfs 1.8G 8.9M 1.8G 1% /run tmpfs 1.8G 0 1.8G 0% /sys/fs/cgroup /dev/sda1 497M 195M 303M 40% /boot tmpfs 369M 0 369M 0% /run/user/0 /dev/sdb1 20G 45M 19G 1% /sdb [root@localhost ~]# cd /sdb [root@localhost sdb]# ls 99-sysctl.conf lost+found [root@localhost sdb]# more 99-sysctl.conf # System default settings live in /usr/lib/sysctl.d/00-system.conf. # To override those settings, enter new settings here, or in an /etc/sysctl.d/<name>.conf file # # For more information, see sysctl.conf(5) and sysctl.d(5).
ext4文件系统修复
[root@localhost ~]# mkfs.ext3 /dev/sdb1
mke2fs 1.42.9 (28-Dec-2013)
Filesystem label=
OS type: Linux
Block size=4096 (log=2)
Fragment size=4096 (log=2)
Stride=0 blocks, Stripe width=0 blocks
1310720 inodes, 5242624 blocks
262131 blocks (5.00%) reserved for the super user
First data block=0
Maximum filesystem blocks=4294967296
160 block groups
32768 blocks per group, 32768 fragments per group
8192 inodes per group
Superblock backups stored on blocks:
32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208,
4096000
Allocating group tables: done
Writing inode tables: done
Creating journal (32768 blocks): done
Writing superblocks and filesystem accounting information: done
[root@localhost ~]# mount /dev/sdb1 /sdb
[root@localhost ~]# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/ol-root 36G 4.0G 32G 12% /
devtmpfs 1.8G 0 1.8G 0% /dev
tmpfs 1.8G 0 1.8G 0% /dev/shm
tmpfs 1.8G 8.9M 1.8G 1% /run
tmpfs 1.8G 0 1.8G 0% /sys/fs/cgroup
/dev/sda1 497M 195M 303M 40% /boot
tmpfs 369M 0 369M 0% /run/user/0
/dev/sdb1 20G 45M 19G 1% /sdb
[root@localhost ~]# dd if=/dev/zero of=/dev/sdb1 bs=1024 count=5
5+0 records in
5+0 records out
5120 bytes (5.1 kB) copied, 0.0138915 s, 369 kB/s
[root@localhost ~]# fsck -t ext3 /dev/sdb1
fsck from util-linux 2.23.2
e2fsck 1.42.9 (28-Dec-2013)
ext2fs_open2: Bad magic number in super-block
fsck.ext3: Superblock invalid, trying backup blocks...
/dev/sdb1 was not cleanly unmounted, check forced.
Pass 1: Checking inodes, blocks, and sizes
Pass 2: Checking directory structure
Pass 3: Checking directory connectivity
Pass 4: Checking reference counts
Pass 5: Checking group summary information
/dev/sdb1: ***** FILE SYSTEM WAS MODIFIED *****
/dev/sdb1: 11/1310720 files (0.0% non-contiguous), 126322/5242624 blocks
[root@localhost ~]# mount /dev/sdb1 /sdb
[root@localhost ~]# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/ol-root 36G 4.0G 32G 12% /
devtmpfs 1.8G 0 1.8G 0% /dev
tmpfs 1.8G 0 1.8G 0% /dev/shm
tmpfs 1.8G 8.9M 1.8G 1% /run
tmpfs 1.8G 0 1.8G 0% /sys/fs/cgroup
/dev/sda1 497M 195M 303M 40% /boot
tmpfs 369M 0 369M 0% /run/user/0
/dev/sdb1 20G 45M 19G 1% /sdb
fsck修复危险性较大,建议先备份对应的分区(dd命令备份分区)然后再处理,有导致分区数据全部或者部分丢失的风险,如果超级块彻底损坏无法恢复,请联系我们，提供专业ORACLE数据库恢复技术支持
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