Hard disk device name:
Everything in linux is a file, so the files of the hard disk are automatically generated and recognized in the kernel. After the recognition, they are placed under /dev, and a corresponding file is generated under one hard disk, and two hard disks will generate consecutive files. The corresponding file, its name is related to the hard disk type, for example: sas interface, sata interface
The name of the virtual disk is
/dev/sd? //following a is the first hard disk, following b is the second hard disk [root@www ~]# ls /dev/sd* /dev/sda /dev/sda1 /dev/sda2 //behind The one, two, and three represent partitions. The name of the virtual disk is /dev/vd /dev/xvd
add hard drive
Refresh to identify the hard drive
[root@www ~]# echo '- - -' > /sys/class/scsi_host/host2/scan //Refresh [root@www ~]# lsblk //It is used to list all available block device information, And it can also show the dependencies between them NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT sda 8:0 0 50G 0 disk ├─sda1 8:1 0 1G 0 part /boot └─sda2 8:2 0 49G 0 part ├ ─centos-root 253:0 0 45.1G 0 lvm / └─centos-swap 253:1 0 3.9G 0 lvm [SWAP] sdb 8:16 0 20G 0 disk sdc 8:32 0 10G 0 disk sr0 11:0 1 4.4G 0 rom
Identify hard disk format
# 1 means mechanical # 0 means SSD [root@www ~]# lsblk -d -o name,rota NAME ROTA sda 1 sdb 1 sdc 1 sr0 1
There are two partition modes MBR and GPT partition
A hard disk in the MBR partition can have up to 4 primary partitions or 3 primary partitions and 1 extended partition (n logical partitions)
The command to create partitions fdisk manages MBR partitions gdisk manages GPT partitions parted Advanced partition operations can be interactive or non-interactive // just a little understanding partproble Synchronize the data in the partition and input partprobe to let the system identify the newly added partition, and then create physical volume
Partitioning tools fdisk and gdisk
p partition list//display partition table t change partition type e logical partition n create new partition d delete partition w save and exit q do not save and exit fdisk /dev/sdb
Logical volume (lvm allows modification of the volume) VG
We group multiple hard disks or partition logic together and we call it volume group VG (volume group)
Implementation process
Designate the device as a physical volume--""Use one or more physical volumes to create a volume group--""Then create a logical volume through the volume group--""Then use the logical volume (partition) by mounting
start testing
Prepare a partition and remember to reformat a hard disk
First turn the physical disk into a physical volume
[root@www ~]# pvcreate /dev/sd{b1,c}
Physical volume "/dev/sdb1" successfully created.
Physical volume "/dev/sdc" successfully created.
[root@www ~]# pvs //查看物理卷
PV VG Fmt Attr PSize PFree
/dev/sda2 centos lvm2 a-- <49.00g 4.00m
/dev/sdb1 lvm2 --- 10.00g 10.00g
/dev/sdc lvm2 --- 10.00g 10.00g
[root@www ~]# pvdisplay
"/dev/sdc" is a new physical volume of "10.00 GiB"
--- NEW Physical volume ---
PV Name /dev/sdc
VG Name
PV Size 10.00 GiB
Allocatable NO
PE Size 0
Total PE 0
Free PE 0
Allocated PE 0
PV UUID f4trEC-xRX1-XfhJ-XCTd-RDnv-FVYT-1blirM
"/dev/sdb1" is a new physical volume of "10.00 GiB"
--- NEW Physical volume ---
PV Name /dev/sdb1
VG Name
PV Size 10.00 GiB
Allocatable NO
PE Size 0
Total PE 0
Free PE 0
Allocated PE 0
PV UUID qKEnlk-oAr1-OfFM-cM7W-jBTP-ZOe3-lPT56V
Add physical volume to volume group
PE is called a physical extent. It is responsible for allocating the smallest unit in the logical volume. For example, the expansion and shrinkage to be used later must use the PE as the unit.
PE size can be specified, the default is 4M
vgcreate -s (specify PE size) 16 vg0 /dev/sd{b1,c}
[root@www ~]# vgcreate vggroup /dev/sd{b1,c}
Volume group "vggroup" successfully created
[root@www ~]# vgs
VG #PV #LV #SN Attr VSize VFree
centos 1 2 0 wz--n- <49.00g 4.00m
vggroup 2 0 0 wz--n- 19.99g 19.99g
[root@www ~]# vgdisplay
--- Volume group ---
VG Name vggroup
System ID
Format lvm2
Metadata Areas 2
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 2
Act PV 2
VG Size 19.99 GiB
PE Size 4.00 MiB
Total PE 5118
Alloc PE / Size 0 / 0
Free PE / Size 5118 / 19.99 GiB
VG UUID Ugx1bj-bL7L-yZcH-btjC-n0dO-0skf-EWDTGa
Divide the volume group into logical volumes
In the logical volume, the PE is called LE pvdisplay, and you can view the logical volume that is separated from the physical volume.
[root@www ~]# lvcreate -n mysql -l 1000 vggroup Logical volume "mysql" created. [root@www ~]# lvs LV VG Attr LSize Pool Origin Data% Meta% Move Log Cpy%Sync Convert root centos -wi-ao---- <45.12g swap centos -wi-ao---- <3.88g mysql vggroup -wi-a----- <3.91g [root@www ~]# lvdisplay --- Logical volume --- LV Path /dev/vggroup/mysql LV Name mysql VG Name vggroup LV UUID IJbyFS-wOjQ-4hpV-iK1x-Fqj9-YO3H-qgWdZ4 LV Write Access read/write LV Creation host, time www, 2023-02-15 15:13:26 +0800 LV Status available # open 0 LV Size <3.91 GiB Current LE 1000 Segments 1 Allocation inherit Read ahead sectors auto - currently set to 8192 Block device 253:2
View the location of the logical volume
[root@www ~]# ll /dev/vggroup/log lrwxrwxrwx 1 root root 7 2月 15 15:20 /dev/vggroup/log -> ../dm-3 [root@www ~]# ll /dev/vggroup/mysql lrwxrwxrwx 1 root root 7 2月 15 15:13 /dev/vggroup/mysql -> ../dm-2
Formatting is to write to the file system, the formatting is very simple, just use mkfs. file system name
create file system
[root@www ~]# mkfs.ext4 /dev/vggroup/mysql mke2fs 1.42.9 (28-Dec-2013) file system label = OS type: Linux block size = 4096 (log = 2) block size = 4096 ( log=2) Stride=0 blocks, Stripe width=0 blocks 256000 inodes, 1024000 blocks 51200 blocks (5.00%) reserved for the super user first data block=0 Maximum filesystem blocks=1048576000 32 block groups 32768 blocks per g roup, 32768 fragments per group 8000 inodes per group Superblock backups stored on blocks: 32768, 98304, 163840, 229376, 294912, 819200, 884736 Allocating group tables: Complete Writing inode table: Complete Creat ing journal (16384 blocks): done Writing superblocks and filesystem accounting information: 完成 [root@www ~]# blkid /dev/sr0: UUID="2020-11-04-11-36-43-00" LABEL="CentOS 7 x86_64" TYPE="iso9660" PTTYPE="dos" /dev/sda1: UUID="4605ff7f-243b-4a27-a39e-52e6cdfe1846" TYPE="xfs" /dev/sda2: UUID="LtW5Jh-Tdbs-XeQE-5oyj-M3m1-1CBf-mqPmRa" TYPE="LVM2_member" /dev/sdb1: UUID="qKEnlk-oAr1-OfFM-cM7W-jBTP-ZOe3-lPT56V" TYPE="LVM2_member" PARTUUID="1ae63c86-a655-44a0-9d50-fb8cab83a8e5" /dev/mapper/centos-root: UUID="a1bb456a-312d-4ad6-805f-ec9e12e701c7" TYPE="xfs" /dev/sdc: UUID="f4trEC-xRX1-XfhJ-XCTd-RDnv-FVYT-1blirM" TYPE="LVM2_member" /dev/mapper/centos-swap: UUID="4d3f8a28-2f87-408f-bda4-74d531098319" TYPE="swap" /dev/mapper/vggroup-mysql: UUID="04e0df52-54b5-42ab-bced-f8f30afce3e4" TYPE="ext4"
mount
vi /etc/fstab /dev/vggroup/mysql /mnt/mysql (mount point) ext4 (file system) defaults 0 0 mkdir -p /mnt/mysql mount -a[root@www ~]# df file system 1K- blocks used available % used mount point devtmpfs 1918592 0 1918592 0% /dev tmpfs 1930644 0 1930644 0% /dev/shm tmpfs 1930644 11800 1918844 1% /run tmpfs 1930644 0 193 0644 0% /sys/fs/cgroup /dev /mapper/centos-root 47285700 1624100 45661600 4% / /dev/sda1 1038336 153892 884444 15% /boot tmpfs 386132 0 386132 0% /run/user/0 /dev/mapper/vggroup-mysql 3966144 15992 3728968 1% /mnt/mysql
Expansion of Logical Volume
lvextend -l 50%free /dev/vggroup/mysql
Size of logical volume vggroup/mysql changed from <3.91 GiB (1000 extents) to <6.09 GiB (1559 extents).
Logical volume vggroup/mysql successfully resized.
Synchronized data
resize2fs /dev /vggroup/mysql
resize2fs 1.42.9 (28-Dec-2013)
Filesystem at /dev/vggroup/mysql is mounted on /mnt/mysql; on-line resizing required
old_desc_blocks = 1, new_desc_blocks = 1
The filesystem on /dev/vggroup /mysql is now 1596416 blocks long.
]# df -Th
file system type capacity used available used % mount point
devtmpfs devtmpfs 1.9G 0 1.9G 0% /dev
tmpfs tmpfs 1.9G 0 1.9G 0% /dev/shm
tmpfs tmpfs 1.9G 12M 1.9G 1% /run
tmpfs tmpfs 1.9G 0 1.9G 0% /sys/fs /cgroup
/dev/mapper/centos-root xfs 46G 1.6G 44G 4% /
/dev/sda1 xfs 1014M 151M 864M 15% /boot
tmpfs tmpfs 378M 0 378M 0% /run/user /0
/dev/mapper/vggroup-mysql ext4 3.8G 16M 3.6G 1% /mnt/mysql
/dev/mapper/vggroup-log xfs 3.9G 33M 3.9G 1% /mnt/log
[root@www ~]# df -Th
file system type capacity used available used% mount point
devtmpfs devtmpfs 1.9G 0 1.9G 0% /dev
tmpfs tmpfs 1.9G 0 1.9G 0% /dev/shm
tmpfs tmpfs 1.9G 12M 1.9G 1% /run
tmpfs tmpfs 1.9G 0 1.9G 0% /sys/fs/cgroup /
dev/mapper/centos-root xfs 46G 1.6G 44G 4% /
/dev/sda1 xfs 1014M 151M 864M 15% /boot
tmpfs tmpfs 378M 0 378M 0% /run/user/0
/dev/mapper/vggroup -mysql ext4 6.0G 16M 5.7G 1% /mnt/mysql
/dev/mapper/vggroup-log xfs 3.9G 33M 3.9G 1% /mnt/log
xfs file system expansion
lvextend -L 1G /dev/vggroup/log
New size given (256 extents) not larger than existing size (1000 extents)
synchronous data
xfs_growfs /mnt/log/
meta-data=/dev/mapper/vggroup-log isize=512 agcount=4, agsize=256000 blks
= sectsz=512 attr =2, projid32bit=1
= crc=1 finobt=0 spinodes=0
data = bsize=4096 blocks=1024000, imaxpct=25
= sunit=0 width=0 blks
naming =version 2 bsize=4096 ascii-ci=0 ftype=1
log =internal bsize=4096 blocks=2560, version=2
= sectsz=512 sunit =0 blks, lazy-count=1
realtime =none extsz=4096 blocks=0, rtextents=0
[root@www ~]# df -h
file system capacity used available available used% mount point
devtmpfs 1.9G 0 1.9G 0% /dev
tmpfs 1.9G 0 1.9G 0% /dev/shm
tmpfs 1.9G 12M 1.9G 1% /run
tmpfs 1.9G 0 1.9G 0% /sys/fs/cgroup
/dev/mapper/centos-root 46G 1.6G 44G 4% /
/dev/sda1 1014M 151M 864M 15% /boot
tmpfs 378M 0 378M 0% /run/user/0
/dev/mapper/vggroup-mysql 6.0G 16M 5.7 G 1% /mnt/mysql
/dev/mapper/vggroup-log 3.9G 33M 3.9G 1% /mnt/log
Re-partition a disk, select it as a physical partition, add it to the vg volume group, and then Expand
fdisk /dev/sdc
pvcreate /dev/sdc1
pvs
vgextend vggroup /dev/sdc1 //Add the new physical volume to the volume group
vgs
vgdisplay
Logical volume shrinkage (xfs does not support shrinkage, it can only be formatted before shrinking, then the data on the volume is gone, and shrinking is meaningless)
The first step is to unmount umount /mnt/mysql/ the second part to check the file (must be done, he will prompt you if you don’t do it) resize2fs /dev/vggroup/mysql 5G resize2fs 1.42.9 (28-Dec-2013) please First run 'e2fsck -f /dev/vggroup/mysql'. e2fsck -f /dev/vggroup/mysql e2fsck 1.42.9 (28-Dec-2013) Step 1: Check inodes, blocks, and sizes Step 2: Check Directory structure Step 3: Check directory connectivity Pass 4: Checking reference counts Step 5: Check cluster summary information /dev/vggroup/mysql: 11/392000 files (0.0% non-contiguous), 44996/1596416 blocks Step 3 Resize resize2fs /dev/vggroup/mysql 5G resize2fs 1.42.9 (28-Dec-2013) Resizing the filesystem on /dev/vggroup/mysql to 1310720 (4k) blocks. The filesystem on /dev/vggroup/mysql is now 1310720 blocks long. The fourth step shrinks the logical volume //The value of the two reductions must be consistent [root@www ~]# lvreduce -L 5G /dev/ vggroup/mysql WARNING: Device for PV f4trEC-xRX1-XfhJ-XCTd-RDnv-FVYT-1blirM not found or rejected by a filter. Couldn't find device with uuid f4trEC -xRX1-XfhJ-XCTd-RDnv-FVYT-1blirM. Cannot change VG vggroup while PVs are missing. Consider vgreduce --removemissing. Cannot process volume group vggroup The fifth step is to remount mount -a The sixth step is to view the reduced df -Th File system type capacity used available used% mount point devtmpfs devtmpfs 1.9G 0 1.9G 0% /dev tmpfs tmpfs 1.9G 0 1.9G 0% /dev/shm tmpfs tmpfs 1.9G 12M 1.9G 1% /run tmpfs tmpfs 1.9G 0 1.9G 0% /sys/fs/cgroup / dev/mapper/centos-root xfs 46G 1.6G 44G 4% / /dev/sda1 xfs 1014M 151M 864M 15% / boot tmpfs tmpfs 378M 0 378M 0% /run/user/0 /dev/mapper/vggroup-log xfs 3.9G 33M 3.9G 1% /mnt/log /dev/mapper/vggroup-mysql ext4 4.9G 16M 4.7G 1% /mnt/mysql
Replace the hard disk in the same volume group
1. First transfer the data pvmove /dev/sdc1 and then delete the volume group vgreduce vggroup /dev/sdc1 and then delete the physical volume pvremove /dev/sdc before removing the hard disk
The same goes for deleting a logical volume
先取消挂载
[root@www ~]# umount /mnt/mysql/
[root@www ~]# umount /mnt/log/
2.先移除逻辑卷
lvremove /dev/vggroup/mysql
WARNING: Device for PV f4trEC-xRX1-XfhJ-XCTd-RDnv-FVYT-1blirM not found or rejected by a filter.
Couldn't find device with uuid f4trEC-xRX1-XfhJ-XCTd-RDnv-FVYT-1blirM.
Do you really want to remove active logical volume vggroup/mysql? [y/n]: y
Logical volume "mysql" successfully removed
[root@www ~]# lvremove /dev/vggroup/log
WARNING: Device for PV f4trEC-xRX1-XfhJ-XCTd-RDnv-FVYT-1blirM not found or rejected by a filter.
Couldn't find device with uuid f4trEC-xRX1-XfhJ-XCTd-RDnv-FVYT-1blirM.
Do you really want to remove active logical volume vggroup/log? [y/n]: y
Logical volume "log" successfully removed
[root@www ~]# lvs
WARNING: Device for PV f4trEC-xRX1-XfhJ-XCTd-RDnv-FVYT-1blirM not found or rejected by a filter. Couldn't
find device with uuid f4trEC-xRX1-XfhJ-XCTd-RDnv-FVYT-1blirM.
LV VG Attr LSize Pool Origin Data% Meta% Move Log Cpy%Sync Convert
root centos -wi-ao---- <45.12g
swap centos -wi-ao---- <3.88g
3. Remove volume group
vgremove vggroup
4. Move Remove the physical volume
pvremove /dev/sd{b1,c1}
5. Delete the file format in fdiskl
and restore to the original hard disk