What is 1 LVM
1.1 Explain the concept
LVM (Logical Volume Manager), a logical volume manager, a plurality of hard disks to the pair of partitions logically combined, as a large hard disk is used.
When the lack of hard disk space, you can dynamically add additional hard disk partition to an existing volume group - dynamic management of disk space.
1.2 Why use LVM
LVM equipment commonly used for large numbers of disks, such as disk array server.
But LVM also applies to only one or two hard drives for small systems.
1.2.1 idea of expansion when not in use LVM
Traditional file systems are partitioned, a file system based on a corresponding one partition, this approach is relatively straightforward, but not easy to change:
(1) different partitions independently of each other, not individual files across partitions to store, prone to hard disk utilization is not balanced;
(2) When a file system / partition is full, the expansion can not be, can only be used to re-partition / filesystem setup, re-partition data loss, it is necessary:
① make migration and backup data;
② or data partition to another partition greater;
③ symbolic links, or by way of other partitions use of space - very troublesome;(3) If you want to merge multiple partitions on the hard drive used together, it can only be used to re-partition the way - need to do backup and recovery of data.
When the idea of the expansion of the use of LVM 1.2.2
When using LVM when technology, the situation is different:
More (1) hard disk partition LVM volume group for the unified management can be easily added or removed a partition - that is, to expand or reduce the available capacity of the volume group, make full use of hard disk space;
(2) file system based on the logical volume, the logical volume can be changed according to the size (capacity range within the volume group) to meet the requirements;
(3) file system is built on LVM, partitions across storage access, more convenient;
It is strongly recommended for systems with multiple disks using LVM disk management.
1.3 Glossary
PV (Physical Volume): physical volume, in the LVM bottom, may be a physical hard disk or partition;
PP (Physical Extend): physical region, PV may be the smallest unit for allocation of memory, can be specified in the creation of the PV, such as 1M, 2M, 4M, 8M ... .. PE composition in the same VG size should be the same for all PV ;
VG (Volume Group): a volume group, based on PV, may contain one to a plurality of the PV;
LV (Logical Volume): logical, built on VG, equivalent to the concept of the original partition, but the size can be changed dynamically.
2 ordinary mount disk method
2.1 Creating the main partition operations
(1) View partitioning - fdisk -l
[root@localhost ~]# fdisk -l Disk /dev/sda: 299.0 GB, 298999349248 bytes # 磁盘/dev/sda 255 heads, 63 sectors/track, 36351 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x4d69fe0e Device Boot Start End Blocks Id System /dev/sda1 * 1 26 204800 83 Linux # 分为2个区, sda1 Partition 1 does not end on cylinder boundary. /dev/sda2 26 36352 291785728 8e Linux LVM # sda2 # 磁盘/dev/sdb没有分区 Disk /dev/sdb: 4000.0 GB, 3999999721472 bytes 255 heads, 63 sectors/track, 486305 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x00000000 ......
(2) reviewing existing disk - lsblk
[the root @ localhost ~] # lsblk NAME the MAJ: the TYPE MOUNTPOINT the RO SIZE MIN RM SDA. 8: 0 0 0 278.5G Disk ├─sda1. 8: Part. 1 0 0 200M / Boot └─sda2. 8: Part 2 0 0 278.3G └ ─VolGroup-LogVol (dm-0) 253: 0 0 1.9T 0 lvm / # LVM partition type sdb 8:32 0 3.7T 0 disk # yet a new disk partitions
(3) the new disk partition - fdisk /dev/sdb
[root@localhost ~]# fdisk /dev/sdb
Device contains neither a valid DOS partition table, nor Sun, SGI or OSF disklabel
Building a new DOS disklabel with disk identifier 0xf91f8c4c.
Changes will remain in memory only, until you decide to write them.
After that, of course, the previous content won't be recoverable.
Warning: invalid flag 0x0000 of partition table 4 will be corrected by w(rite)
WARNING: The size of this disk is 4.0 TB (4000225165312 bytes).
DOS partition table format can not be used on drives for volumes
larger than (2199023255040 bytes) for 512-byte sectors. Use parted(1) and GUID
partition table format (GPT).
WARNING: DOS-compatible mode is deprecated. It's strongly recommended to
The MODE OFF Switch (Command 'C') and the display Change Units to
sectors (Command 'U').
the Command (m for Help): n-n-# represents the new partition
the Command Action
E Extended
P Primary Partition (1-4)
P # P represents a partition type primary partition, the primary partition is only one to four select
partition number (1-4): 1 # primary partition number
First cylinder (1-486333, default 1) : # start sector numbers, directly enter, default value. 1
the using default value. 1
# end sector number, the default --- value here only half a new disk is loaded (2T), so it needs to create a partition / dev / sdb2 again using the remaining half.
Last Cylinder, or Cylinders + size + {K, M, G} (l- 267 349, default 267 349):
the Using default value 267 349
the Command (m for Help): W # write disposed above the partition table and exit
of the partition table has been Altered!
the Calling the ioctl () to Re-Read partition table.
Syncing Disks.
(4) Check again partitioning - fdisk -l
More out of a / dev / sdb1 area, that is, before the specified partition number 1 after the primary partition.
[root@localhost ~]# fdisk -l Disk /dev/sda: 299.0 GB, 298999349248 bytes 255 heads, 63 sectors/track, 36351 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x4d69fe0e Device Boot Start End Blocks Id System /dev/sda1 * 1 26 204800 83 Linux Partition 1 does not end on cylinder boundary. /dev/sda2 26 36352 291785728 8e Linux LVM # /dev/sdb磁盘: Disk /dev/sdb: 4000.0 GB, 3999999721472 bytes 255 heads, 63 sectors/track, 486305 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x8f3043b5 # 多出来的分区/dev/sdb1 Device Boot Start End Blocks Id System /dev/sdb1 1 267349 2147480811 83 Linux ......
(5) view the partition information for the current partition table - cat /proc/partitions
[the root @ localhost ~] # CAT / proc / Partitions Major Minor #blocks name . 8 0 291 991 552 SDA . 8. 1 204800 sda1 . 8 2 291 785 728 sda2 . 8 3,906,249,728 SDB # 32 adding a new disk new partition 8 33 2147480811 sdb1 # created 25302046660608 dm-0
If after you've created, cat / proc / partitions to see less than the corresponding partition, use parprobe Refresh command:
[root@localhost ~]# partprobe /dev/sdc
2.2 format the new partition
(1) to format the new partition - mkfs -t
It is recommended that the new partition is formatted as ext4 file types, as well as ext2, ext3 and other file types, please refer to the difference between blog ext2, ext3 and ext4 the difference .
[root@localhost ~]# mkfs -t ext4 /dev/sdb1
mke2fs 1.41.12 (17-May-2010)
Filesystem label=
OS type: Linux
Block size=4096 (log=2)
Fragment size=4096 (log=2)
Stride=0 blocks, Stripe width=0 blocks
134217728 inodes, 536870202 blocks
26843510 blocks (5.00%) reserved for the super user
First data block=0
Maximum filesystem blocks=4294967296
16384 block groups
32768 blocks per group, 32768 fragments per group
8192 inodes per group
Superblock backups stored on blocks:
32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208,
4096000, 7962624, 11239424, 20480000, 23887872, 71663616, 78675968,
102400000, 214990848, 512000000
Writing inode tables: 8874/16384
(2) After waiting for a little while, the following prompt appears, indicating that the format is complete:
Writing inode tables: done Creating journal (32768 blocks): done Writing superblocks and filesystem accounting information: done This filesystem will be automatically checked every 26 mounts or 180 days, whichever comes first. Use tune2fs -c or -i to override.
2.3 Mounting the New Partition
(1) Create a directory, and / dev / sdb1 hanging on to the directory:
[root@localhost /]# mkdir data && cd /data [root@localhost data]# mount /dev/sdc1 /data1
(2) Check the mount is successful:
[root@localhost data]# df -l Filesystem 1K-blocks Used Available Use% Mounted on /dev/mapper/VolGroup-LogVol 286901696 18601728 253726196 7% / tmpfs 66020980 0 66020980 0% /dev/shm /dev/sda1 495844 33476 436768 8% /boot # 挂载成功: /dev/sdb1 2113784984 202776 2006208168 1% /data
Automatically mount the boot provided 2.4
Edit the file / etc / fstab:
[root@localhost data]# vim /etc/fstab # 文件内容如下: # /etc/fstab # Created by anaconda on Wed Sep 12 10:41:40 2018 # # Accessible filesystems, by reference, are maintained under '/dev/disk' # See man pages fstab(5), findfs(8), mount(8) and/or blkid(8) for more info # /dev/mapper/VolGroup-LogVol / ext4 defaults 1 1 /dev/sdb1 /data ext4 defaults 1 1 UUID=22b1d425-d050-43c3-a735-06d48bbb9051 /boot ext4 defaults 1 2 tmpfs /dev/shm tmpfs defaults 0 0 devpts /dev/pts devpts gid=5,mode=620 0 0 sysfs /sys sysfs defaults 0 0 proc /proc proc defaults 0 0
3 LVM mount the disk - Recommended
3.1 Viewing disk capacity information
[root@localhost ~]# df -h Filesystem Size Used Avail Use% Mounted on /dev/mapper/VG-LogVol 1.9T 1.8T 61G 97% / # LVM卷组-逻辑卷 tmpfs 63G 0 63G 0% /dev/shm /dev/sda1 485M 40M 421M 9% /boot
3.2 Viewing disk sector information
[the root @ localhost ~] # the fdisk -l Disk / dev / SDA: 299.0 GB, disk # 298 999 349 248 bytes / dev / SDA 255 Heads, 63 is sectors / Track, 36351 Cylinders Units = Cylinders of 16065 * 512 = 8.22528 million bytes Sector size ( Logical / PHYSICAL): 512 bytes / 512 bytes the I / O size (Minimum / Optimal): 512 bytes / 512 bytes Disk identifier: 0x4d69fe0e Device Id the Boot the Start End Blocks the System / dev / sda1. 1 * 83 204800 26 is divided into the Linux # 2 districts, sda1 partition 1 does not End ON Cylinder boundary. / dev / sda2 26 36 352 291 785 728 8E sda2 Linux LVM # LVM type # newly added disk / dev / sdb, not a partition disk / dev / sdb: 4000.0 GB , 3999999721472 bytes 255 heads, 63 sectors/track, 486305 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x00000000 # LVM格式的卷组信息: Disk /dev/mapper/VolGroup-LogVol: 4294 MB, 4294967296 bytes 255 heads, 63 sectors/track, 522 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x00000000
3.3 Creating partitions
[root@localhost ~]# fdisk /dev/sdb
Device contains neither a valid DOS partition table, nor Sun, SGI or OSF disklabel
Building a new DOS disklabel with disk identifier 0x5b3d66ba.
Changes will remain in memory only, until you decide to write them.
After that, of course, the previous content won't be recoverable.
Warning: invalid flag 0x0000 of partition table 4 will be corrected by w(rite)
WARNING: The size of this disk is 4.0 TB (3999999721472 bytes).
DOS partition table format can not be used on drives for volumes
larger than (2199023255040 bytes) for 512-byte sectors. Use parted(1) and GUID
partition table format (GPT).
WARNING: DOS-compatible mode is deprecated. It's strongly recommended to
switch off the mode (command 'c') and change display units to
sectors (command 'u').
Command (m for help): n # 添加分区
Command action
e extended
p primary partition (1-4)
p # 添加主分区
Partition number (1-4): 1 # 1号主分区, 即/dev/sdb1
First cylinder (1-486305, default 1):
Using default value 1
Last cylinder, +cylinders or +size{K,M,G} (1-267349, default 267349): 486305
Value out of range.
Last cylinder, +cylinders or +size{K,M,G} (1-267349, default 267349):
Using default value 267349
Command (m for help): n # 继续添加分区
Command action
e extended
p primary partition (1-4)
p
Partition number (1-4): 2 # 2号主分区, 即/dev/sdc2
First cylinder (267350-486305, default 267350):
Using default value 267350
Last cylinder, +cylinders or +size{K,M,G} (267350-486305, default 486305):
Using default value 486305
Command (m for help): p # 打印分区信息:
Disk /dev/sdb: 4000.0 GB, 3999999721472 bytes
255 heads, 63 sectors/track, 486305 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x5b3d66ba
Device Boot Start End Blocks Id System
/ dev / sdb1. 1 83 267 349 2,147,480,811 the Linux
/ dev / sdb2 267 350 83 486 305 1,758,764,070 the Linux
the Command (m for Help): T # conversion type
the Partition Number (1-4):. 1
the Partition Number (1-4): Review. 1 # / dev / sdb1 as Linux LVM type:
Hex code (type L to List Codes): L # See available type:
0 Empty 24 the NEC the DOS 81 the Minix / Old Lin BF the Solaris
. 1 FAT12 39 Plan. 9 82 the Linux the swap / So C1 DRDOS / sec (FAT-
2. 3C PartitionMagic the root 83 XENIX C4 DRDOS the Linux / sec (FAT-
. 3 XENIX Venix 80286 84 40 usr the OS / 2 hidden C: C6 DRDOS / sec (FAT-
. 4 the FAT16 <85 32M 41 is the Linux the PPC the PReP the Boot Extended C7 Syrinx
5 Extended 42 SFS 86 NTFS volume set da Non-FS data
6 FAT16 4d QNX4.x 87 NTFS volume set db CP/M / CTOS / .
7 HPFS/NTFS 4e QNX4.x 2nd part 88 Linux plaintext de Dell Utility
8 AIX 4f QNX4.x 3rd part 8e Linux LVM df BootIt
9 AIX bootable 50 OnTrack DM 93 Amoeba e1 DOS access
a OS/2 Boot Manag 51 OnTrack DM6 Aux 94 Amoeba BBT e3 DOS R/O
b W95 FAT32 52 CP/M 9f BSD/OS e4 SpeedStor
c W95 FAT32 (LBA) 53 OnTrack DM6 Aux a0 IBM Thinkpad hi eb BeOS fs
e W95 FAT16 (LBA) 54 OnTrackDM6 a5 FreeBSD ee GPT
f W95 Ext'd (LBA) 55 EZ-Drive a6 OpenBSD ef EFI (FAT-12/16/
10 OPUS 56 Golden Bow a7 NeXTSTEP f0 Linux/PA-RISC b
11 Hidden FAT12 5c Priam Edisk a8 Darwin UFS f1 SpeedStor
12 Compaq diagnost 61 SpeedStor a9 NetBSD f4 SpeedStor
14 Hidden FAT16 <3 63 GNU HURD or Sys ab Darwin boot f2 DOS secondary
16 Hidden FAT16 64 Novell Netware af HFS / HFS+ fb VMware VMFS
17 Hidden HPFS/NTF 65 Novell Netware b7 BSDI fs fc VMware VMKCORE
18 AST SmartSleep 70 DiskSecure Mult b8 BSDI swap fd Linux raid auto
1b Hidden W95 FAT3 75 PC/IX bb Boot Wizard hid fe LANstep
1C Hidden W95 the FAT3 80 Old the Minix BE the Solaris Boot FF BBT
1E Hidden W95 the FAT1
Hex code (type L to List Codes): 8E # modified to 8e, i.e., Linux LVM type
the Changed System type of Partition. 1 to 8E (Linux LVM)
the Command ( Help for m): T
the Partition Number (1-4): 2 # modify / dev / sdc2 Linux LVM type is
Hex code (type L to List Codes): 8E
the Changed type of System Partition 2 to 8E (Linux LVM)
the Command ( m for help): p # again to view information:
Disk / dev / SDC: 4000.0 GB, 3999999721472 bytes
255 Heads, 63 is sectors / Track, 486 305 Cylinders
Units = Cylinders of 16065 * 512 = 8.22528 million bytes
Sector size (Logical / PHYSICAL) : 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x5b3d66ba
Device Boot Start End Blocks Id System
/dev/sdb1 1 267349 2147480811 8e Linux LVM # Id已改变
/dev/sdb2 267350 486305 1758764070 8e Linux LVM
Command (m for help): w # 保存并退出
The partition table has been altered! # 修改成功
Calling ioctl() to re-read partition table.
Syncing disks.
3.4 Creating Physical Volumes
[root@localhost ~]# pvcreate /dev/sdb1 Physical volume "/dev/sdb1" successfully created [root@localhost ~]# pvcreate /dev/sdb2 Physical volume "/dev/sdb2" successfully created
3.5 extend the volume group
# View existing volume group, the volume group found that the volume group is the need for expansion, you do not have to create a volume group again, but directly expand the volume group can be: [root @ localhost ~] # Vgs of the VG #PV #LV #SN Attr vfree VSize volgroup WZ 2 2 0 - 0 N- 1.91T # expansion volume group: [the root @ localhost ~] # the vgextend volgroup / dev / sdb1 volume group "volgroup" extended successfully [the root @ localhost ~] # the vgextend volgroup / dev / sdb2 Volume Group "volgroup" successfully Extended
Note: If the following information to the physical disk can not be mounted in a volume group, indicating that this physical disk has been mounted, the need to uninstall, and then perform operations to create partitions + volume group:
[root@localhost /]# vgextend VolGroup /dev/sdb1 No physical volume label read from /dev/sdb1 Physical volume /dev/sdb1 not found Can't open /dev/sdb1 exclusively. Mounted filesystem? Unable to add physical volume '/dev/sdb1' to volume group 'VolGroup'.
3.6 Extending a Logical Volume
# Logical volume expansion, i.e., expansion: [the root @ localhost ~] # 100 + -l% the lvextend the FREE / dev / Mapper / volgroup-LogVol the Extending Logical Volume lv_root to 5.54 of TiB the Logical Volume lv_root successfully Resized # above command is all idle are the logical volume expansion space, the expansion of the size can also be specified: the lvextend 100G + -l / dev / Mapper / volgroup-LogVol
3.7 View disk volume group information
[root@localhost ~]# lsblk NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT sda 8:0 0 278.5G 0 disk ├─sda1 8:1 0 500M 0 part /boot └─sda2 8:2 0 278G 0 part ├─VolGroup-LogVol (dm-0) 253:0 0 5.6T 0 lvm / sdb 8:16 0 1.6T 0 disk └─sdb1 8:17 0 1.6T 0 part └─VolGroup-LogVol (dm-0) 253:0 0 5.6T 0 lvm / sdc 8:32 0 3.7T 0 disk ├─sdc1 8:33 0 2T 0 part │ └─VolGroup-LogVol (dm-0) 253:0 0 5.6T 0 lvm / └─sdc2 8:34 0 1.7T 0 part └─VolGroup-LogVol (dm-0) 253:0 0 5.6T 0 lvm /
3.8 Adjusting the size of the file system
Reread the disk size # 7: [the root @ localhost ~] # xfs_growfs / dev / Mapper / volgroup-LogVol xfs_growfs: / dev / Mapper / A Not volgroup IS-LogVol Mounted the XFS filesystem # 6.5 reread the CentOS disk size: # ext4 format, resize2fs goes through the entire disk, slower, but does not affect the reading and writing of data, so that it can run in the background. [the root @ localhost ~] # resize2fs / dev / Mapper / volgroup-LogVol resize2fs 1.41.12 (17- On May-2010) the Filesystem AT / dev / Mapper / volgroup-LogVol IS Mounted ON /; ON-Line Resizing required Old desc_blocks = 122, new_desc_blocks = 355 Performing AN ON-Line a resize of / dev / Mapper / volgroup-lv_root to 1487098880 ( . 4K) Blocks # waited almost 20 minutes, which came out the following goods: at the filesystem ON / dev / Mapper / volgroup-LogVol IS now 1,487,098,880 Long Blocks. # expansion quickly look achievements it: [root@localhost ~]# df -h Filesystem Size Used Avail Use% Mounted on /dev/mapper/VolGroup-LogVol 5.5T 1.8T 3.5T 34% / # 扩容成功 tmpfs 63G 0 63G 0% /dev/shm /dev/sda1 485M 40M 421M 9% /boot
3.9 Appendix - create a volume group
The corresponding [3.5] section expansion volume group, if the volume group does not exist, create it. VolGroup following is the volume group name.
volgroup the vgcreate / dev / sdb1 # Create a logical volume name:. mylv (operating system will produce: / dev / VolGroup / mylv directory) # current volume group 100G space allocated to the logical volume lvcreate -L 100G VolGroup mylv -n # is assigned to all or all of the free space in the current logical volumes in the volume group: the lvcreate -l + 100% mylv the fREE volgroup -n # formatted logical volume group: the mkfs -t ext4 / dev / volgroup / mylv # to mount the volume group to the specified directory, if it is mounted to the root directory, there is no need to add items to the start / etc / fstab file. Mount -t ext4 / dev / volgroup / mylv / Data