RAID与磁盘管理之——综合应用
为了实现磁盘的管理和RAID的综合，现将四块硬盘组合成一个RAID10，并在此基础之上创建物理卷、卷组、逻辑卷，实现在线扩容，最后挂载使用。
其中也部分包含了swap分区的创建和使用。
1、根据linux系统下，一切皆文件的特性。硬盘在linux中识别为文件，分区也是识别为文件，因此在liunx系统之中用一块磁盘的四个主分区（主分区最多四个）模拟成四块SCSI硬盘。
首先进行四个主分区的创建：
[root@localhost ~]# fdisk /dev/sdb
Welcome to fdisk (util-linux 2.23.2).
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.
Be careful before using the write command.
Device does not contain a recognized partition table
Building a new DOS disklabel with disk identifier 0xdbd4718a.
Building a new DOS disklabel with disk identifier 0xdbd4718a.
Command (m for help): n
Partition type:
p primary (0 primary, 0 extended, 4 free)
e extended
Select (default p):
Using default response p
Partition number (1-4, default 1):
First sector (2048-20971519, default 2048):
Using default value 2048
Last sector, +sectors or +size{K,M,G} (2048-20971519, default 20971519): +2500M
Partition 1 of type Linux and of size 2.5 GiB is set
Partition type:
p primary (0 primary, 0 extended, 4 free)
e extended
Select (default p):
Using default response p
Partition number (1-4, default 1):
First sector (2048-20971519, default 2048):
Using default value 2048
Last sector, +sectors or +size{K,M,G} (2048-20971519, default 20971519): +2500M
Partition 1 of type Linux and of size 2.5 GiB is set
Command (m for help): n
Partition type:
p primary (1 primary, 0 extended, 3 free)
e extended
Select (default p):
Using default response p
Partition number (2-4, default 2):
First sector (5122048-20971519, default 5122048):
Using default value 5122048
Last sector, +sectors or +size{K,M,G} (5122048-20971519, default 20971519): +2500M
Partition 2 of type Linux and of size 2.5 GiB is set
Partition type:
p primary (1 primary, 0 extended, 3 free)
e extended
Select (default p):
Using default response p
Partition number (2-4, default 2):
First sector (5122048-20971519, default 5122048):
Using default value 5122048
Last sector, +sectors or +size{K,M,G} (5122048-20971519, default 20971519): +2500M
Partition 2 of type Linux and of size 2.5 GiB is set
Command (m for help): n
Partition type:
p primary (2 primary, 0 extended, 2 free)
e extended
Select (default p):
Using default response p
Partition number (3,4, default 3):
First sector (10242048-20971519, default 10242048):
Using default value 10242048
Last sector, +sectors or +size{K,M,G} (10242048-20971519, default 20971519): +2500M
Partition 3 of type Linux and of size 2.5 GiB is set
Partition type:
p primary (2 primary, 0 extended, 2 free)
e extended
Select (default p):
Using default response p
Partition number (3,4, default 3):
First sector (10242048-20971519, default 10242048):
Using default value 10242048
Last sector, +sectors or +size{K,M,G} (10242048-20971519, default 20971519): +2500M
Partition 3 of type Linux and of size 2.5 GiB is set
Command (m for help): n
Partition type:
p primary (3 primary, 0 extended, 1 free)
e extended
Select (default e): p
Selected partition 4
First sector (15362048-20971519, default 15362048):
Using default value 15362048
Last sector, +sectors or +size{K,M,G} (15362048-20971519, default 20971519):
Using default value 20971519
Partition 4 of type Linux and of size 2.7 GiB is set
Partition type:
p primary (3 primary, 0 extended, 1 free)
e extended
Select (default e): p
Selected partition 4
First sector (15362048-20971519, default 15362048):
Using default value 15362048
Last sector, +sectors or +size{K,M,G} (15362048-20971519, default 20971519):
Using default value 20971519
Partition 4 of type Linux and of size 2.7 GiB is set
Command (m for help): w
The partition table has been altered!
The partition table has been altered!
Calling ioctl() to re-read partition table.
Syncing disks.
Syncing disks.
2、磁盘同步完成之后开始创建RAID10
[root@localhost ~]# ls /dev/sdb*
/dev/sdb /dev/sdb1 /dev/sdb2 /dev/sdb3 /dev/sdb4
[root@localhost ~]# rpm -q mdadm
mdadm-3.4-14.el7.x86_64
/dev/sdb /dev/sdb1 /dev/sdb2 /dev/sdb3 /dev/sdb4
[root@localhost ~]# rpm -q mdadm
mdadm-3.4-14.el7.x86_64
所有的RAID需要mdadm软件包来统一管理。
[root@localhost dev]# mdadm -C /dev/md/md_10 -l 10 -n 4 /dev/sdb{1..4}
mdadm: largest drive (/dev/sdb4) exceeds size (2557952K) by more than 1%
Continue creating array? y
mdadm: Defaulting to version 1.2 metadata
mdadm: array /dev/md/md_10 started.
mdadm: largest drive (/dev/sdb4) exceeds size (2557952K) by more than 1%
Continue creating array? y
mdadm: Defaulting to version 1.2 metadata
mdadm: array /dev/md/md_10 started.
RAID10创建成功，进到/dev/md/进行查看：
[root@localhost dev]# cd md
[root@localhost md]# ls
md_10
[root@localhost md]# ls
md_10
3、创建物理卷、卷组——该卷组中只包含了一个物理卷。
[root@localhost dev]# pvcreate /dev/md/md_10
Physical volume "/dev/md/md_10" successfully created.
[root@localhost dev]# vgcreate /dev/vg_10 /dev/md/md_10
Volume group "vg_10" successfully created
Physical volume "/dev/md/md_10" successfully created.
[root@localhost dev]# vgcreate /dev/vg_10 /dev/md/md_10
Volume group "vg_10" successfully created
如果需要增加物理卷：
pvcreste 新的物理卷名
pvscan ——查看新的可用物理卷
vgextend 卷组名 可用物理卷名
4、创建逻辑卷
[root@localhost dev]# lvcreate -L 1000M -n lv_10 /dev/vg_10
Logical volume "lv_10" created.
Logical volume "lv_10" created.
进行查看：进到/dev/vg_10
[root@localhost dev]# cd vg_10/
[root@localhost vg_10]# ls
lv_10
[root@localhost vg_10]# ls
lv_10
5、格式化后挂载使用
[root@localhost dev]# mkfs -t xfs /dev/vg_10/lv_10
meta-data=/dev/vg_10/lv_10 isize=512 agcount=8, agsize=31872 blks
= sectsz=512 attr=2, projid32bit=1
= crc=1 finobt=0, sparse=0
data = bsize=4096 blocks=254976, imaxpct=25
= sunit=128 swidth=256 blks
naming =version 2 bsize=4096 ascii-ci=0 ftype=1
log =internal log bsize=4096 blocks=624, version=2
= sectsz=512 sunit=8 blks, lazy-count=1
realtime =none extsz=4096 blocks=0, rtextents=0
meta-data=/dev/vg_10/lv_10 isize=512 agcount=8, agsize=31872 blks
= sectsz=512 attr=2, projid32bit=1
= crc=1 finobt=0, sparse=0
data = bsize=4096 blocks=254976, imaxpct=25
= sunit=128 swidth=256 blks
naming =version 2 bsize=4096 ascii-ci=0 ftype=1
log =internal log bsize=4096 blocks=624, version=2
= sectsz=512 sunit=8 blks, lazy-count=1
realtime =none extsz=4096 blocks=0, rtextents=0
[root@localhost ~]# mkdir /md_mount
[root@localhost ~]# mount /dev/vg_10/lv_10 /md_mount/
[root@localhost ~]# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/sda2 8.7G 4.7G 4.1G 54% /
devtmpfs 474M 0 474M 0% /dev
tmpfs 489M 84K 489M 1% /dev/shm
tmpfs 489M 7.1M 482M 2% /run
tmpfs 489M 0 489M 0% /sys/fs/cgroup
/dev/sda1 297M 152M 146M 51% /boot
tmpfs 98M 0 98M 0% /run/user/0
tmpfs 98M 16K 98M 1% /run/user/42
/dev/mapper/vg_10-lv_10 994M 33M 962M 4% /md_mount
[root@localhost ~]# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/sda2 8.7G 4.7G 4.1G 54% /
devtmpfs 474M 0 474M 0% /dev
tmpfs 489M 84K 489M 1% /dev/shm
tmpfs 489M 7.1M 482M 2% /run
tmpfs 489M 0 489M 0% /sys/fs/cgroup
/dev/sda1 297M 152M 146M 51% /boot
tmpfs 98M 0 98M 0% /run/user/0
tmpfs 98M 16K 98M 1% /run/user/42
/dev/mapper/vg_10-lv_10 994M 33M 962M 4% /md_mount
然后会发现/dev/mapper/vg_10-lv_10和设置的路径不太一样，怎么回事？
[root@localhost ~]# ls /dev/mapper/vg_10-lv_10 -l
lrwxrwxrwx 1 root root 7 Jul 14 18:48 /dev/mapper/vg_10-lv_10 -> ../dm-0
lrwxrwxrwx 1 root root 7 Jul 14 18:48 /dev/mapper/vg_10-lv_10 -> ../dm-0
仔细查看之后发现是链接文件，指向了目的地。
6、在线扩容
[root@localhost ~]# lvextend -L 2000M /dev/vg_10/lv_10
Size of logical volume vg_10/lv_10 changed from 1000.00 MiB (250 extents) to 1.95 GiB (500 extents).
Logical volume vg_10/lv_10 successfully resized.
Size of logical volume vg_10/lv_10 changed from 1000.00 MiB (250 extents) to 1.95 GiB (500 extents).
Logical volume vg_10/lv_10 successfully resized.
扩容之后文件系统也需要扩展：
[root@localhost ~]# xfs_growfs /dev/vg_10/lv_10
meta-data=/dev/mapper/vg_10-lv_10 isize=512 agcount=8, agsize=31872 blks
= sectsz=512 attr=2, projid32bit=1
= crc=1 finobt=0 spinodes=0
data = bsize=4096 blocks=254976, imaxpct=25
= sunit=128 swidth=256 blks
naming =version 2 bsize=4096 ascii-ci=0 ftype=1
log =internal bsize=4096 blocks=624, version=2
= sectsz=512 sunit=8 blks, lazy-count=1
realtime =none extsz=4096 blocks=0, rtextents=0
data blocks changed from 254976 to 512000
meta-data=/dev/mapper/vg_10-lv_10 isize=512 agcount=8, agsize=31872 blks
= sectsz=512 attr=2, projid32bit=1
= crc=1 finobt=0 spinodes=0
data = bsize=4096 blocks=254976, imaxpct=25
= sunit=128 swidth=256 blks
naming =version 2 bsize=4096 ascii-ci=0 ftype=1
log =internal bsize=4096 blocks=624, version=2
= sectsz=512 sunit=8 blks, lazy-count=1
realtime =none extsz=4096 blocks=0, rtextents=0
data blocks changed from 254976 to 512000
查看扩容之后的大小：
[root@localhost ~]# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/sda2 8.7G 4.7G 4.1G 54% /
devtmpfs 474M 0 474M 0% /dev
tmpfs 489M 84K 489M 1% /dev/shm
tmpfs 489M 7.1M 482M 2% /run
tmpfs 489M 0 489M 0% /sys/fs/cgroup
/dev/sda1 297M 152M 146M 51% /boot
tmpfs 98M 0 98M 0% /run/user/0
tmpfs 98M 16K 98M 1% /run/user/42
/dev/mapper/vg_10-lv_10 2.0G 33M 2.0G 2% /md_mount
Filesystem Size Used Avail Use% Mounted on
/dev/sda2 8.7G 4.7G 4.1G 54% /
devtmpfs 474M 0 474M 0% /dev
tmpfs 489M 84K 489M 1% /dev/shm
tmpfs 489M 7.1M 482M 2% /run
tmpfs 489M 0 489M 0% /sys/fs/cgroup
/dev/sda1 297M 152M 146M 51% /boot
tmpfs 98M 0 98M 0% /run/user/0
tmpfs 98M 16K 98M 1% /run/user/42
/dev/mapper/vg_10-lv_10 2.0G 33M 2.0G 2% /md_mount
扩容成功，从RAID到逻辑卷的创建完成！
7、swap交换分区
[root@localhost ~]# mkdir /swap
[root@localhost ~]# dd if=/dev/zero of=/swap/swap bs=1M count=512
512+0 records in
512+0 records out
536870912 bytes (537 MB) copied, 8.01682 s, 67.0 MB/s
[root@localhost ~]# mkswap /swap/swap
Setting up swapspace version 1, size = 524284 KiB
no label, UUID=49054206-a32f-443e-b87b-22619a2aead4
512+0 records in
512+0 records out
536870912 bytes (537 MB) copied, 8.01682 s, 67.0 MB/s
[root@localhost ~]# mkswap /swap/swap
Setting up swapspace version 1, size = 524284 KiB
no label, UUID=49054206-a32f-443e-b87b-22619a2aead4
[root@localhost ~]# free -h
total used free shared buff/cache available
Mem: 976M 239M 71M 7.1M 665M 553M
Swap: 1.0G 0B 1.0G
[root@localhost ~]# swapon /swap/swap
swapon: /swap/swap: insecure permissions 0644, 0600 suggested.
[root@localhost ~]# chmod 600 /swap/swap
[root@localhost ~]# free -h
total used free shared buff/cache available
Mem: 976M 239M 68M 7.1M 668M 553M
Swap: 1.5G 0B 1.5G
total used free shared buff/cache available
Mem: 976M 239M 71M 7.1M 665M 553M
Swap: 1.0G 0B 1.0G
[root@localhost ~]# swapon /swap/swap
swapon: /swap/swap: insecure permissions 0644, 0600 suggested.
[root@localhost ~]# chmod 600 /swap/swap
[root@localhost ~]# free -h
total used free shared buff/cache available
Mem: 976M 239M 68M 7.1M 668M 553M
Swap: 1.5G 0B 1.5G
交换分区添加成功。
实现开机自启：
echo “/swap/swap swap swap defaults 0 0” >> /etc/fstab
完成！
