PV,VG,LV
迪丽瓦拉
2024-05-31 16:05:11
0次
名词解析
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PV（Physical volume）：物理卷
A Volume Group (VG) is a collection of one or more physical devices, each called a Physical Volume (PV).
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VG（Volume group）：卷组
Each block of data in an LV is stored on one or more PV in the VG, according to algorithms implemented by Device Mapper (DM) in the kernel.
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LV（Logical volume）：逻辑卷
A Logical Volume (LV) is a virtual block device that can be used by the system or applications.
先从感官上来认识PV/VG/LV
# 查看物理设备，当前环境中存在两个盘/dev/nvme0n1p1和/dev/sda
[root@192 home]# fdisk -l
Disk /dev/nvme0n1: 50 GiB, 53687091200 bytes, 104857600 sectors
Disk model: VMware Virtual NVMe Disk
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: dos
Disk identifier: 0x6d7c9360Device Boot Start End Sectors Size Id Type
/dev/nvme0n1p1 * 2048 2099199 2097152 1G 83 Linux
/dev/nvme0n1p2 2099200 104857599 102758400 49G 8e Linux LVMDisk /dev/sda: 20 GiB, 21474836480 bytes, 41943040 sectors
Disk model: VMware Virtual S
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: dos
Disk identifier: 0x94c9d806Device Boot Start End Sectors Size Id Type
/dev/sda1 2048 10500000 10497953 5G 83 Linux
/dev/sda2 10500096 21000000 10499905 5G 83 Linux# 查看物理卷
[root@192 home]# pvdisplay --- Physical volume ---PV Name /dev/nvme0n1p2VG Name cs_192PV Size <49.00 GiB / not usable 3.00 MiBAllocatable yes (but full)PE Size 4.00 MiBTotal PE 12543Free PE 0Allocated PE 12543PV UUID eUvMTe-qQVn-Jq28-QIDH-HLH8-5lbY-1b9sOh[root@192 home]# vgdisplay --- Volume group ---VG Name cs_192System ID Format lvm2Metadata Areas 1Metadata Sequence No 3VG Access read/writeVG Status resizableMAX LV 0Cur LV 2Open LV 2Max PV 0Cur PV 1Act PV 1VG Size <49.00 GiBPE Size 4.00 MiBTotal PE 12543Alloc PE / Size 12543 / <49.00 GiBFree PE / Size 0 / 0 VG UUID 1GLOYb-51tp-sG78-cZcl-VQkc-dq6r-q0J7k3[root@192 home]# lvdisplay --- Logical volume ---LV Path /dev/cs_192/swapLV Name swapVG Name cs_192LV UUID tpUazx-0ikg-27P0-hKvs-7Are-62t1-WH1EkALV Write Access read/writeLV Creation host, time 192.168.0.100, 2023-03-08 07:45:16 +0800LV Status available# open 2LV Size 5.00 GiBCurrent LE 1280Segments 1Allocation inheritRead ahead sectors auto- currently set to 256Block device 253:1--- Logical volume ---LV Path /dev/cs_192/rootLV Name rootVG Name cs_192LV UUID H8Vzp4-KtbR-Fms7-hI8U-IVjz-5ofl-LMt1H1LV Write Access read/writeLV Creation host, time 192.168.0.100, 2023-03-08 07:45:16 +0800LV Status available# open 1LV Size <44.00 GiBCurrent LE 11263Segments 1Allocation inheritRead ahead sectors auto- currently set to 256Block device 253:0创建和管理LVM（Logic Volume Manage）
什么是LVM
The Logical Volume Manager (LVM) provides tools to create virtual block devices from physical devices.
两种管理方式
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基于分区的方式
基于分区的方式，需要事先通过fdisk或者其他方式对磁盘分区，分区之后不格式化文件系统，然后再用pvcreate来创建物理卷
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基于磁盘的方式
基于磁盘的方式，直接对磁盘创建物理卷（PV），然后分配卷组（VG），再在卷组里面添加逻辑卷（LV）
本次着重描述第二种方式，一般适用于专属服务器，比如数据库服务器，整个磁盘都是为数据库服务而设的，可以根据数据库服务的需求，直接划分出数据盘，备份盘，归档盘等等。
查看物理盘
查看服务器挂载的块设备，对应于实际的物理磁盘，也就是pv命令操作的对象（physical devices）。
[root@192 curtis]# fdisk -l
Disk /dev/nvme0n1: 50 GiB, 53687091200 bytes, 104857600 sectors
Disk model: VMware Virtual NVMe Disk
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: dos
Disk identifier: 0x6d7c9360Device Boot Start End Sectors Size Id Type
/dev/nvme0n1p1 * 2048 2099199 2097152 1G 83 Linux
/dev/nvme0n1p2 2099200 104857599 102758400 49G 8e Linux LVMDisk /dev/sda: 20 GiB, 21474836480 bytes, 41943040 sectors
Disk model: VMware Virtual S
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: dos
Disk identifier: 0x94c9d806Device Boot Start End Sectors Size Id Type
/dev/sda1 2048 10500000 10497953 5G 83 Linux
/dev/sda2 10500096 21000000 10499905 5G 83 Linux# 以/dev/sdb为示例创建物理卷
Disk /dev/sdb: 10 GiB, 10737418240 bytes, 20971520 sectors
Disk model: VMware Virtual S
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
创建物理卷
# 格式：pvcreate 物理磁盘对应的块设备名
[root@sndsdevdb01 ~]#pvcreate /dev/vda
# 查看已创建的物理卷
[root@192 curtis]# pvcreate /dev/sdb Physical volume "/dev/sdb" successfully created.
[root@192 curtis]# pvscan PV /dev/nvme0n1p2 VG cs_192 lvm2 [<49.00 GiB / 0 free]PV /dev/sdb lvm2 [10.00 GiB]Total: 2 [<59.00 GiB] / in use: 1 [<49.00 GiB] / in no VG: 1 [10.00 GiB]
[root@192 curtis]# pvdisplay --- Physical volume ---PV Name /dev/nvme0n1p2VG Name cs_192PV Size <49.00 GiB / not usable 3.00 MiBAllocatable yes (but full)PE Size 4.00 MiBTotal PE 12543Free PE 0Allocated PE 12543PV UUID eUvMTe-qQVn-Jq28-QIDH-HLH8-5lbY-1b9sOh"/dev/sdb" is a new physical volume of "10.00 GiB"--- NEW Physical volume ---PV Name /dev/sdb # 物理卷名VG Name PV Size 10.00 GiB # 物理卷大小Allocatable NOPE Size 0 Total PE 0Free PE 0Allocated PE 0PV UUID GawNUd-Cd2Z-ikP0-CA9Z-Pny1-Jzg9-c81sTv
创建卷组
# 格式：vgcreate 卷组名 物理卷名
[root@192 curtis]# vgcreate scsi_vg /dev/sdb Volume group "scsi_vg" successfully created
[root@192 curtis]# vgscan Found volume group "scsi_vg" using metadata type lvm2Found volume group "cs_192" using metadata type lvm2
[root@192 curtis]# vgdisplay --- Volume group ---VG Name scsi_vgSystem ID Format lvm2Metadata Areas 1Metadata Sequence No 1VG Access read/writeVG Status resizableMAX LV 0Cur LV 0Open LV 0Max PV 0Cur PV 1Act PV 1VG Size <10.00 GiBPE Size 4.00 MiBTotal PE 2559Alloc PE / Size 0 / 0 Free PE / Size 2559 / <10.00 GiBVG UUID x596pX-kWJ1-RCNp-B372-P4kN-rWwC-nOQ8N2--- Volume group ---VG Name cs_192System ID Format lvm2Metadata Areas 1Metadata Sequence No 3VG Access read/writeVG Status resizableMAX LV 0Cur LV 2Open LV 2Max PV 0Cur PV 1Act PV 1VG Size <49.00 GiBPE Size 4.00 MiBTotal PE 12543Alloc PE / Size 12543 / <49.00 GiBFree PE / Size 0 / 0 VG UUID 1GLOYb-51tp-sG78-cZcl-VQkc-dq6r-q0J7k3
创建逻辑卷
# 格式： lvcreate -n 逻辑卷名 -L 逻辑卷大小 卷组名
[root@192 curtis]# lvcreate -n scsi_vl_01 -L 5G scsi_vgLogical volume "scsi_vl_01" created.
[root@192 curtis]# lvdisplay --- Logical volume ---LV Path /dev/scsi_vg/scsi_vl_01LV Name scsi_vl_01VG Name scsi_vgLV UUID PjwnV4-30q2-AWC1-6uZ5-q1KJ-iPDm-qDonaMLV Write Access read/writeLV Creation host, time 192.168.0.100, 2023-03-09 07:55:05 +0800LV Status available# open 0LV Size 5.00 GiBCurrent LE 1280Segments 1Allocation inheritRead ahead sectors auto- currently set to 256Block device 253:2
...# fdisk -l也可以查看对应的逻辑卷可以直接使用了
[root@192 curtis]# fdisk -l
...
Disk /dev/mapper/scsi_vg-scsi_vl_01: 5 GiB, 5368709120 bytes, 10485760 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
...
上述LV还没有被格式化文件系统，属于裸设备，如需要存储数据，还需要对LV进行mkfs操作
格式化文件系统
以ext4文件系统类型为例
# 格式： mkfs.ext3 LV对应的块设备名
[root@192 curtis]# mkfs.ext4 /dev/mapper/scsi_vg-scsi_vl_01
mke2fs 1.46.5 (30-Dec-2021)
Creating filesystem with 1310720 4k blocks and 327680 inodes
Filesystem UUID: c4043f33-d2e9-46e1-b637-0d99cb52b127
Superblock backups stored on blocks: 32768, 98304, 163840, 229376, 294912, 819200, 884736Allocating group tables: done
Writing inode tables: done
Creating journal (16384 blocks): done
Writing superblocks and filesystem accounting information: done
挂载使用
# mount [-t vfstype] [-o options] [设备名称] [挂载点]
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挂载点:
必须是一个已经存在的目录，这个目录可以不为空，但挂载后这个目录下以前的内容将不可用，umount以后会恢复正常。
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设备名称:
可以是一个分区，一个usb设备，光驱，软盘，网络共享等
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-t
指定文件系统的类型，通常不必指定。mount 会自动选择正确的类型。
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-o
主要用来描述设备或档案的挂接方式。常用的参数有：
loop：用来把一个文件当成硬盘分区挂接上系统;
ro：采用只读方式挂接设备;
rw：采用读写方式挂接设备;
iocharset：指定访问文件系统所用字符集
[root@192 curtis]# cd /mnt/
[root@192 mnt]# mkdir storage
[root@192 mnt]# ls
hgfs storage
[root@192 mnt]# mount -o rw /dev/mapper/scsi_vg-scsi_vl_01 /mnt/storage/
[root@192 mnt]# df -h
Filesystem Size Used Avail Use% Mounted on
devtmpfs 4.0M 0 4.0M 0% /dev
tmpfs 3.8G 0 3.8G 0% /dev/shm
tmpfs 1.5G 9.7M 1.5G 1% /run
/dev/mapper/cs_192-root 44G 4.3G 40G 10% /
/dev/nvme0n1p1 1014M 292M 723M 29% /boot
tmpfs 767M 100K 766M 1% /run/user/1000
/dev/mapper/scsi_vg-scsi_vl_01 4.9G 24K 4.6G 1% /mnt/storage
扩展LV的大小
系统使用一段时间后，可能LV的空间已经满了，或者一开始操作有误，空间给小了，需要扩展大小，可以使用lvextend命令
首先先确认卷组中是否有剩余空间
[root@192 mnt]# vgdisplay --- Volume group ---VG Name scsi_vgSystem ID Format lvm2Metadata Areas 1Metadata Sequence No 2VG Access read/writeVG Status resizableMAX LV 0Cur LV 1Open LV 1Max PV 0Cur PV 1Act PV 1VG Size <10.00 GiBPE Size 4.00 MiBTotal PE 2559Alloc PE / Size 1280 / 5.00 GiB # 已分配空间 (scsi_vl_01)Free PE / Size 1279 / <5.00 GiB # 剩余空间VG UUID x596pX-kWJ1-RCNp-B372-P4kN-rWwC-nOQ8N2- 如果
Free PE / Size还有空间，并且剩余的空间能满足扩展需求，那么可以直接用lvextend命令。
# 格式： lvextend -L +10G lv块设备名
# 注意要有加号，否则就表示将该lv扩展至10G[root@192 mnt]# umount /mnt/storage
[root@192 mnt]# lvextend -L +2G /dev/mapper/scsi_vg-scsi_vl_01Size of logical volume scsi_vg/scsi_vl_01 changed from 5.00 GiB (1280 extents) to 7.00 GiB (1792 extents).Logical volume scsi_vg/scsi_vl_01 successfully resized.[root@192 mnt]# fdisk -l
Disk /dev/mapper/scsi_vg-scsi_vl_01: 7 GiB, 7516192768 bytes, 14680064 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
扩展完成后，还需补充格式化新扩展的卷的文件系统，否则df -hl是看不到扩展的大小。
[root@192 mnt]# mount -o rw /dev/mapper/scsi_vg-scsi_vl_01 /mnt/storage/
[root@192 mnt]# df -h
Filesystem Size Used Avail Use% Mounted on
devtmpfs 4.0M 0 4.0M 0% /dev
tmpfs 3.8G 0 3.8G 0% /dev/shm
tmpfs 1.5G 9.7M 1.5G 1% /run
/dev/mapper/cs_192-root 44G 4.3G 40G 10% /
/dev/nvme0n1p1 1014M 292M 723M 29% /boot
tmpfs 767M 100K 766M 1% /run/user/1000
/dev/mapper/scsi_vg-scsi_vl_01 4.9G 24K 4.6G 1% /mnt/storage
[root@192 mnt]# umount /mnt/storage
[root@192 mnt]# resize2fs /dev/mapper/scsi_vg-scsi_vl_01
resize2fs 1.46.5 (30-Dec-2021)
Please run 'e2fsck -f /dev/mapper/scsi_vg-scsi_vl_01' first.[root@192 mnt]# e2fsck -f /dev/mapper/scsi_vg-scsi_vl_01
e2fsck 1.46.5 (30-Dec-2021)
Pass 1: Checking inodes, blocks, and sizes
Pass 2: Checking directory structure
Pass 3: Checking directory connectivity
Pass 4: Checking reference counts
Pass 5: Checking group summary information
/dev/mapper/scsi_vg-scsi_vl_01: 11/327680 files (0.0% non-contiguous), 42078/1310720 blocks
[root@192 mnt]# resize2fs /dev/mapper/scsi_vg-scsi_vl_01
resize2fs 1.46.5 (30-Dec-2021)
Resizing the filesystem on /dev/mapper/scsi_vg-scsi_vl_01 to 1835008 (4k) blocks.
The filesystem on /dev/mapper/scsi_vg-scsi_vl_01 is now 1835008 (4k) blocks long.[root@192 mnt]# mount -o rw /dev/mapper/scsi_vg-scsi_vl_01 /mnt/storage/
[root@192 mnt]# df -h
Filesystem Size Used Avail Use% Mounted on
devtmpfs 4.0M 0 4.0M 0% /dev
tmpfs 3.8G 0 3.8G 0% /dev/shm
tmpfs 1.5G 9.7M 1.5G 1% /run
/dev/mapper/cs_192-root 44G 4.3G 40G 10% /
/dev/nvme0n1p1 1014M 292M 723M 29% /boot
tmpfs 767M 100K 766M 1% /run/user/1000
/dev/mapper/scsi_vg-scsi_vl_01 6.9G 24K 6.5G 1% /mnt/storage
- VG中已经没有剩余空间了，那么就需要追加挂载磁盘，然后重新创建新的PV，然后加到当前的VG中（vgextend），然后才是LV的扩展。