Linux 磁盘管理

Linux 创建磁盘 以及磁盘分区管理

查看磁盘信息
[root@ZZSRV2 ~]# fdisk -l

Disk /dev/sda: 42.9 GB, 42949672960 bytes, 83886080 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk label type: dos
Disk identifier: 0x000af460

Device Boot Start End Blocks Id System
/dev/sda1 * 2048 1026047 512000 83 Linux
/dev/sda2 1026048 83886079 41430016 8e Linux LVM

Disk /dev/mapper/centos_zzsrv1-swap: 2181 MB, 2181038080 bytes, 4259840 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes

Disk /dev/mapper/centos_zzsrv1-root: 40.2 GB, 40240152576 bytes, 78594048 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes

添加一块磁盘后重新扫描磁盘不需要重新启动

[root@ZZSRV2 ~]# echo "- - -" > /sys/class/scsi_host/host0/scan
[root@ZZSRV2 ~]# echo "- - -" > /sys/class/scsi_host/host1/scan
[root@ZZSRV2 ~]# echo "- - -" > /sys/class/scsi_host/host2/scan

[root@ZZSRV2 ~]# fdisk -l 再次查看磁盘信息，最下面就会看到新加的磁盘sdb

Disk /dev/sda: 42.9 GB, 42949672960 bytes, 83886080 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk label type: dos
Disk identifier: 0x000af460

Device Boot Start End Blocks Id System
/dev/sda1 * 2048 1026047 512000 83 Linux
/dev/sda2 1026048 83886079 41430016 8e Linux LVM

Disk /dev/mapper/centos_zzsrv1-swap: 2181 MB, 2181038080 bytes, 4259840 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes

Disk /dev/mapper/centos_zzsrv1-root: 40.2 GB, 40240152576 bytes, 78594048 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes

Disk /dev/sdb: 21.5 GB, 21474836480 bytes, 41943040 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes

将磁盘分区（这里是将磁盘分一个区）

[root@ZZSRV2 ~]# fdisk /dev/sdb
Welcome to fdisk (util-linux 2.23.2).

Changes will remain in memory only, until you decide to write them.
Be careful before using the write command.

Device does not contain a recognized partition table
Building a new DOS disklabel with disk identifier 0x7d9737a7.

Command (m for help): n
Partition type:
p primary (0 primary, 0 extended, 4 free)
e extended
Select (default p): p
Partition number (1-4, default 1): →这里是可以将磁盘分几个区
First sector (2048-41943039, default 2048):
Using default value 2048
Last sector, +sectors or +size{K,M,G} (2048-41943039, default 41943039): →分区的大小不可以超过磁盘的大小
Using default value 41943039
Partition 1 of type Linux and of size 20 GiB is set

Command (m for help): p

Disk /dev/sdb: 21.5 GB, 21474836480 bytes, 41943040 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk label type: dos
Disk identifier: 0x7d9737a7

Device Boot Start End Blocks Id System
/dev/sdb1 2048 41943039 20970496 83 Linux

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

Calling ioctl() to re-read partition table.
Syncing disks.

创建PV
[root@ZZSRV2 ~]# pvscan
PV /dev/sda2 VG centos_zzsrv1 lvm2 [39.51 GiB / 0 free]
Total: 1 [39.51 GiB] / in use: 1 [39.51 GiB] / in no VG: 0 [0 ]
[root@ZZSRV2 ~]# pvcreate /dev/sdb1
Physical volume "/dev/sdb1" successfully created
[root@ZZSRV2 ~]# pvscan
PV /dev/sda2 VG centos_zzsrv1 lvm2 [39.51 GiB / 0 free]
PV /dev/sdb1 lvm2 [20.00 GiB]
Total: 2 [59.51 GiB] / in use: 1 [39.51 GiB] / in no VG: 1 [20.00 GiB]

创建VG

[root@ZZSRV2 ~]# vgscan
Reading all physical volumes. This may take a while...
Found volume group "centos_zzsrv1" using metadata type lvm2
[root@ZZSRV2 ~]# vgcreate VG /dev/sdb1
Volume group "VG" successfully created
[root@ZZSRV2 ~]# vgscan
Reading all physical volumes. This may take a while...
Found volume group "VG" using metadata type lvm2
Found volume group "centos_zzsrv1" using metadata type lvm2

[root@ZZSRV2 ~]# vgdisplay VG
--- Volume group ---
VG Name VG
System ID
Format lvm2
Metadata Areas 1
Metadata Sequence No 1
VG Access read/write
VG Status resizable
MAX LV 0
Cur LV 0
Open LV 0
Max PV 0
Cur PV 1
Act PV 1
VG Size 20.00 GiB
PE Size 4.00 MiB
Total PE 5119 →记着这个数字
Alloc PE / Size 0 / 0
Free PE / Size 5119 / 20.00 GiB
VG UUID qHpcWT-mjRd-xcsT-QBac-XM94-b1H4-P2NQdF

创建一个LV，使用VG的全部PE

[root@ZZSRV2 ~]# lvscan
ACTIVE '/dev/centos_zzsrv1/swap' [2.03 GiB] inherit
ACTIVE '/dev/centos_zzsrv1/root' [37.48 GiB] inherit

LV的名称为LV1
[root@ZZSRV2 ~]# lvcreate -n LV1 -l 5119 VG
Logical volume "LV1" created

[root@ZZSRV2 ~]# lvscan
ACTIVE '/dev/VG/LV1' [20.00 GiB] inherit
ACTIVE '/dev/centos_zzsrv1/swap' [2.03 GiB] inherit
ACTIVE '/dev/centos_zzsrv1/root' [37.48 GiB] inherit
[root@ZZSRV2 ~]# lvdisplay /dev/VG/LV1
--- Logical volume ---
LV Path /dev/VG/LV1
LV Name LV1
VG Name VG
LV UUID 2OHuKM-6wyj-7TFr-lJCT-ZfzH-OcKd-f6oLr8
LV Write Access read/write
LV Creation host, time ZZSRV2.localdomain, 2014-08-20 10:31:10 +0800
LV Status available
# open 0
LV Size 20.00 GiB
Current LE 5119
Segments 1
Allocation inherit
Read ahead sectors auto
- currently set to 8192
Block device 253:2

[root@ZZSRV2 ~]# vgdisplay VG
--- Volume group ---
VG Name VG
System ID
Format lvm2
Metadata Areas 1
Metadata Sequence No 2
VG Access read/write
VG Status resizable
MAX LV 0
Cur LV 1
Open LV 0
Max PV 0
Cur PV 1
Act PV 1
VG Size 20.00 GiB
PE Size 4.00 MiB
Total PE 5119
Alloc PE / Size 5119 / 20.00 GiB
Free PE / Size 0 / 0 →注意这儿，已经没有剩余空间，说明全部的空间已经被使用
VG UUID qHpcWT-mjRd-xcsT-QBac-XM94-b1H4-P2NQdF