RHEL 6 文件系统

1.磁盘基本信息
[root@atyu30 ~]# fdisk -l

Disk /dev/sda: 8589 MB, 8589934592 bytes
255 heads, 63 sectors/track, 1044 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x000bbc4e

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1   *           1          64      512000   83  Linux
Partition 1 does not end on cylinder boundary.
/dev/sda2              64        1045     7875584   83  Linux

Disk /dev/sdb: 16.1 GB, 16106127360 bytes
255 heads, 63 sectors/track, 1958 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000

Disk /dev/sdb doesn't contain a valid partition table

Disk /dev/dm-0: 8062 MB, 8062500864 bytes
255 heads, 63 sectors/track, 980 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000

Disk /dev/dm-0 doesn't contain a valid partition table

Disk /dev/dm-1: 6014 MB, 6014631936 bytes
255 heads, 63 sectors/track, 731 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000

Disk /dev/dm-1 doesn't contain a valid partition table

Disk /dev/dm-2: 2046 MB, 2046820352 bytes
255 heads, 63 sectors/track, 248 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000

Disk /dev/dm-2 doesn't contain a valid partition table

2.RHEL 6 ext4 扩容：

[root@atyu30 ~]# fdisk /dev/sdb
Device contains neither a valid DOS partition table, nor Sun, SGI or OSF disklabel
Building a new DOS disklabel with disk identifier 0x5ca4b32e.
Changes will remain in memory only, until you decide to write them.
After that, of course, the previous content won't be recoverable.

Warning: invalid flag 0x0000 of partition table 4 will be corrected by w(rite)

WARNING: DOS-compatible mode is deprecated. It's strongly recommended to
         switch off the mode (command 'c') and change display units to
         sectors (command 'u').

Command (m for help): n
Command action
   e   extended
   p   primary partition (1-4)
p
Partition number (1-4): 1
First cylinder (1-1958, default 1):
Using default value 1
Last cylinder, +cylinders or +size{K,M,G} (1-1958, default 1958):
Using default value 1958

Command (m for help): w
The partition table has been altered!

Calling ioctl() to re-read partition table.
Syncing disks.
[root@atyu30 ~]# mkfs.ext4 /dev/sdb1
mke2fs 1.41.12 (17-May-2010)
文件系统标签=
操作系统:Linux
块大小=4096 (log=2)
分块大小=4096 (log=2)
Stride=0 blocks, Stripe width=0 blocks
983040 inodes, 3931900 blocks
196595 blocks (5.00%) reserved for the super user
第一个数据块=0
Maximum filesystem blocks=4026531840
120 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

正在写入inode表: 完成                           
Creating journal (32768 blocks): 完成
Writing superblocks and filesystem accounting information: 完成

This filesystem will be automatically checked every 36 mounts or
180 days, whichever comes first.  Use tune2fs -c or -i to override.
[root@atyu30 opt]# vi /etc/fstab

#
# /etc/fstab
# Created by anaconda on Fri Nov 19 21:03:21 2010
#
# Accessible filesystems, by reference, are maintained under '/dev/disk'
# See man pages fstab(5), findfs(8), mount(8) and/or blkid(8) for more info
#
/dev/mapper/vg_wiki-lv_root /                       ext4    defaults        1 1
UUID=331a444c-1c11-4e5f-9c25-12ef4e517ed1 /boot                   ext4    defaults        1 2
/dev/mapper/vg_wiki-lv_swap swap                    swap    defaults        0 0
tmpfs                   /dev/shm                tmpfs   defaults        0 0
devpts                  /dev/pts                devpts  gid=5,mode=620  0 0
sysfs                   /sys                    sysfs   defaults        0 0
proc                    /proc                   proc    defaults        0 0
# Add this line
/dev/sdb1                    /opt               ext4    defaults        1 1

[root@atyu30 opt]# df -h
文件系统              容量  已用  可用 已用%% 挂载点
/dev/mapper/vg_wiki-lv_root
                      5.6G  2.5G  2.8G  48% /
tmpfs                 487M     0  487M   0% /dev/shm
/dev/sda1             485M   30M  430M   7% /boot
[root@atyu30 opt]# mount -a
[root@atyu30 opt]# df -h
文件系统              容量  已用  可用 已用%% 挂载点
/dev/mapper/vg_wiki-lv_root
                      5.6G  2.5G  2.8G  48% /
tmpfs                 487M     0  487M   0% /dev/shm
/dev/sda1             485M   30M  430M   7% /boot
/dev/sdb1              15G  166M   14G   2% /opt