西部开源学习笔记BOOK2-《unit 5》

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####### unit5.lvm #######
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lvm的逻辑关系：
物理分区--->pv物理卷---->vg物理卷组----->取出一部分的叫lvm
/\
||组成
pe（卷的最小单位）
注意：那vg可不可以无限扩大？ 不可以
因为xfs文件系统最大支持18EB，超过的话就无法管理。

######1.创建物理分区########
[root@desktop19 ~]# fdisk /dev/vdb
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 0x0e7029a1.
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): +500M
Partition 1 of type Linux and of size 500 MiB 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 (1026048-20971519, default 1026048):
Using default value 1026048
Last sector, +sectors or +size{K,M,G} (1026048-20971519, default 20971519): +500M
Partition 2 of type Linux and of size 500 MiB is set
Command (m for help): t
Partition number (1,2, default 2):
Hex code (type L to list all codes): 8e ##分区id号:8e Linux LVM
Changed type of partition 'Linux' to 'Linux LVM'
Command (m for help): t
Partition number (1,2, default 2): 1
Hex code (type L to list all codes): 8e
Changed type of partition 'Linux' to 'Linux LVM'
Command (m for help): p
Disk /dev/vdb: 10.7 GB, 10737418240 bytes, 20971520 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: 0x0e7029a1
Device Boot Start End Blocks Id System
/dev/vdb1 2048 1026047 512000 8e Linux LVM
/dev/vdb2 1026048 2050047 512000 8e Linux LVM
Command (m for help): wq
The partition table has been altered!
Calling ioctl() to re-read partition table.
Syncing disks.
[root@desktop19 ~]# partprobe

#######2.创建lvm#######
[root@desktop19 ~]# pvcreate /dev/vdb1 ##创建pv
Physical volume "/dev/vdb1" successfully created
[root@desktop19 ~]# vgcreate tbr /dev/vdb1 ##创建vg，取名为tbr，包含/dev/vdb1
Volume group "tbr" successfully created
[root@desktop19 ~]# lvcreate -L 100M -n lv0 tbr ##
Logical volume "lv0" created
[root@desktop19 ~]# mkfs.xfs /dev/tbr/lv0
meta-data=/dev/tbr/lv0 isize=256 agcount=4, agsize=6400 blks
= sectsz=512 attr=2, projid32bit=1
= crc=0
data = bsize=4096 blocks=25600, imaxpct=25
= sunit=0 swidth=0 blks
naming =version 2 bsize=4096 ascii-ci=0 ftype=0
log =internal log bsize=4096 blocks=853, version=2
= sectsz=512 sunit=0 blks, lazy-count=1
realtime =none extsz=4096 blocks=0, rtextents=0
[root@desktop19 ~]# mount /dev/tbr/lv0 /mnt/
[root@desktop19 ~]# df
Filesystem 1K-blocks Used Available Use% Mounted on
/dev/vda1 10473900 3119952 7353948 30% /
devtmpfs 927072 0 927072 0% /dev
tmpfs 942660 80 942580 1% /dev/shm
tmpfs 942660 17040 925620 2% /run
tmpfs 942660 0 942660 0% /sys/fs/cgroup
/dev/mapper/tbr-lv0 98988 5280 93708 6% /mnt
[root@desktop19 ~]# ll /dev/tbr/lv0
lrwxrwxrwx. 1 root root 7 11月 6 01:29 /dev/tbr/lv0 -> ../dm-0
[root@desktop19 ~]# ll /dev/mapper/tbr-lv0
lrwxrwxrwx. 1 root root 7 11月 6 01:29 /dev/mapper/tbr-lv0 -> ../dm-0
[root@desktop19 ~]# watch -n 1 'echo "===pvinfo===";pvs;echo "===vginfo===";vgs;echo
"===lvinfo===";lvs;df -h /mnt'
===pvinfo===
PV VG Fmt Attr PSize PFree
/dev/vdb1 tbr lvm2 a-- 496.00m 396.00m
===vginfo===
VG #PV #LV #SN Attr VSize VFree
tbr 1 1 0 wz--n- 496.00m 396.00m
===lvinfo===
LV VG Attr LSize Pool Origin Data% Move Log Cpy%Sync Convert
lv0 tbr -wi-ao---- 100.00m
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/tbr-lv0 97M 5.2M 92M 6% /mnt

############2.扩展lvm############
[root@desktop19 ~]# lvcreate -L 100M -n lv0 tbr
Logical volume "lv0" created
[root@desktop19 ~]# mkfs.xfs /dev/tbr/lv0
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/tbr-lv0 297M 5.5M 292M 2% /mnt
[root@desktop19 ~]# lvextend -L 200M /dev/tbr/lv0
Extending logical volume lv0 to 200.00 MiB
Logical volume lv0 successfully resized
[root@desktop19 ~]# lvextend -L 500M /dev/tbr/lv0
Extending logical volume lv0 to 500.00 MiB
Insufficient free space: 75 extents needed, but only 74 available
[root@desktop19 ~]# lvextend -L 300M /dev/tbr/lv0
Extending logical volume lv0 to 300.00 MiB
Logical volume lv0 successfully resized
[root@desktop19 ~]# xfs_growfs /dev/tbr/lv0
[root@desktop19 ~]# pvcreate /dev/vdb2
Physical volume "/dev/vdb2" successfully created
[root@desktop19 ~]# vgextend tbr /dev/vdb2
Volume group "tbr" successfully extended
[root@desktop19 ~]# lvextend -L 600M /dev/tbr/lv0
Extending logical volume lv0 to 600.00 MiB
Logical volume lv0 successfully resized
===pvinfo===
PV VG Fmt Attr PSize PFree
/dev/vdb1 tbr lvm2 a-- 496.00m 0
/dev/vdb2 tbr lvm2 a-- 496.00m 392.00m
===vginfo===
VG #PV #LV #SN Attr VSize VFree
tbr 2 1 0 wz--n- 992.00m 392.00m
===lvinfo===
LV VG Attr LSize Pool Origin Data% Move Log Cpy%Sync Convert
lv0 tbr -wi-ao---- 600.00m
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/tbr-lv0 297M 5.5M 292M 2% /mnt
[root@desktop19 ~]# xfs_growfs /dev/tbr/lv0
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/tbr-lv0 597M 5.8M 591M 1% /mnt

#############3.缩减lvm##############
[root@desktop19 ~]# umount /mnt
[root@desktop19 ~]# mkfs.ext4 /dev/tbr/lv0
[root@desktop19 ~]# e2fsck -f /dev/tbr/lv0
[root@desktop19 ~]# resize2fs /dev/tbr/lv0 400M
[root@desktop19 ~]# mount /dev/tbr/lv0 /mnt/
[root@desktop19 ~]# lvreduce -L 400M /dev/tbr/lv0
WARNING: Reducing active and open logical volume to 400.00 MiB
THIS MAY DESTROY YOUR DATA (filesystem etc.)
Do you really want to reduce lv0? [y/n]: y
Reducing logical volume lv0 to 400.00 MiB
Logical volume lv0 successfully resized
[root@desktop19 ~]# pvmove /dev/vdb1 /dev/vdb2
/dev/vdb1: Moved: 13.0%
/dev/vdb1: Moved: 100.0%
[root@desktop19 ~]# vgreduce tbr /dev/vdb1
===pvinfo===
PV VG Fmt Attr PSize PFree
/dev/vdb1 lvm2 a-- 500.00m 500.00m
/dev/vdb2 tbr lvm2 a-- 496.00m 96.00m
[root@desktop19 ~]# pvremove /dev/vdb1
===pvinfo===
PV VG Fmt Attr PSize PFree
/dev/vdb2 tbr lvm2 a-- 496.00m 96.00m
pvmove的时候耐心等待，不要ctrl+c（操作数据时要小心）

#####特殊情况#####
1.如果先缩减了物理卷组的大小，而没有缩减文件系统的大小。（卸载再挂载之后会有问题）
需要卸载2次的问题：##df查看时，只显示第一次挂载的设备
[root@desktop19 ~]# lvcreate -L 10M -n lv0-backup -s /dev/tbr/lv0
Rounding up size to full physical extent 12.00 MiB
Logical volume "lv0-backup" created
[root@desktop19 ~]# mount /dev/tbr/lv0-backup /mnt
[root@desktop19 ~]# df
Filesystem 1K-blocks Used Available Use% Mounted on
/dev/vda1 10473900 3123860 7350040 30% /
devtmpfs 927072 0 927072 0% /dev
tmpfs 942660 80 942580 1% /dev/shm
tmpfs 942660 17056 925604 2% /run
tmpfs 942660 0 942660 0% /sys/fs/cgroup
/dev/mapper/tbr-lv0 588352 912 551972 1% /mnt
[root@desktop19 ~]# umount /mnt/
[root@desktop19 ~]# df
Filesystem 1K-blocks Used Available Use% Mounted on
/dev/vda1 10473900 3123860 7350040 30% /
devtmpfs 927072 0 927072 0% /dev
tmpfs 942660 80 942580 1% /dev/shm
tmpfs 942660 17056 925604 2% /run
tmpfs 942660 0 942660 0% /sys/fs/cgroup
/dev/mapper/tbr-lv0 588352 912 551972 1% /mnt
[root@desktop19 ~]# umount /mnt/
[root@desktop19 ~]# df
Filesystem 1K-blocks Used Available Use% Mounted on
/dev/vda1 10473900 3123860 7350040 30% /
devtmpfs 927072 0 927072 0% /dev
tmpfs 942660 80 942580 1% /dev/shm
tmpfs 942660 17056 925604 2% /run
tmpfs 942660 0 942660 0% /sys/fs/cgroup