公司有台服务器做了raid1，由于容量小，需扩容，原先打算再添加两块硬盘进去做多一组raid1，组成两组raid1混合使用，但是公司抠门，买到服务器只能安装3块硬盘，无奈之下只能放多一块进去单独挂载分区使用。
开始的时候把新加的硬盘接入raid卡，服务器开机无法识别，解决方法是把新加的硬盘接入主板的SATA接口，服务器开机登录后顺利识别到。
先说说开始时候的操作方法：
首先用fdisk进行分区
# fdisk /dev/sdb
整块硬盘全部空间只建立一个分区，分完区后查看
Disk /dev/sdb: 1000.2 GB, 1000204886016 bytes
255 heads, 63 sectors/track, 121601 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: 0x0005f698
Device Boot Start End Blocks Id System
/dev/sdb1 1 121601 976760001 83 Linux
可以看到建立了一个新分区/dev/sdb1
然后进行格式化并挂载分区
# mkfs -t ext4 -c /dev/sdb1 (快速格式化：mkfs.ext4 /dev/sdb1)
mke2fs 1.41.12 (17-May-2010)
Filesystem label=
OS type: Linux
Block size=4096 (log=2)
Fragment size=4096 (log=2)
Stride=0 blocks, Stripe width=0 blocks
61054976 inodes, 244190000 blocks
12209500 blocks (5.00%) reserved for the super user
First data block=0
Maximum filesystem blocks=4294967296
7453 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, 7962624, 11239424, 20480000, 23887872, 71663616, 78675968,
102400000, 214990848
Checking for bad blocks (read-only test): done
Writing inode tables: done
Creating journal (32768 blocks): done
Writing superblocks and filesystem accounting information: done
This filesystem will be automatically checked every 24 mounts or
180 days, whichever comes first. Use tune2fs -c or -i to override.
# mount /dev/sdb1 /data
# df -h
可以看到已经成功挂载了
修改/etc/fstab，添加下面这行，使之开机自动挂载
/dev/sdb1 /data ext4 defaults 0 0
保存后重启服务器init 6
执行df -h发现竟然没有挂载成功
执行fdisk -l还能看到/dev/sdb1分区
Disk /dev/sdb: 1000.2 GB, 1000204886016 bytes
255 heads, 63 sectors/track, 121601 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: 0x0005f698
Device Boot Start End Blocks Id System
/dev/sdb1 1 121601 976760001 83 Linux
但是没有存在/dev/sdb1
# ll /dev/sdb1
ls: cannot access /dev/sdb1: No such file or directory
重新执行挂载
# mount /dev/sdb1 /data/
mount: you must specify the filesystem type
加上分区类型重新挂载，提示不存在分区
# mount -t ext4 /dev/sdb1 /data/
mount: special device /dev/sdb1 does not exist
按照网上大神的方法，成功解决：
# mkfs.ext4 /dev/sdb
mke2fs 1.41.12 (17-May-2010)
/dev/sdb is entire device, not just one partition!
Proceed anyway? (y,n) y
Filesystem label=
OS type: Linux
Block size=4096 (log=2)
Fragment size=4096 (log=2)
Stride=0 blocks, Stripe width=0 blocks
61054976 inodes, 244190646 blocks
12209532 blocks (5.00%) reserved for the super user
First data block=0
Maximum filesystem blocks=4294967296
7453 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, 7962624, 11239424, 20480000, 23887872, 71663616, 78675968,
102400000, 214990848
Writing inode tables: done
Creating journal (32768 blocks): done
Writing superblocks and filesystem accounting information: done
This filesystem will be automatically checked every 23 mounts or
180 days, whichever comes first. Use tune2fs -c or -i to override.
格式化整块硬盘
格式化完毕后fdisk -l查看
Disk /dev/sdb: 1000.2 GB, 1000204886016 bytes
255 heads, 63 sectors/track, 121601 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
没有了/dev/sdb1分区
重新挂载
# mount /dev/sdb /data/
# df -h
成功挂载，修改/etc/fstab使之开机自动挂载，添加以下内容
/dev/sdb /data ext4 defaults 0 0
init 6重启后发现能正常自动挂载，到此已成功解决问题
用lsblk命令查看已识别的硬盘和挂载的分区
# lsblk
