Linux partition expansion (root partition expansion, SWAP partition expansion, mount new partition as directory)
During the running process of Linux system, there is insufficient disk space and what should I do if I need to expand capacity?
This article describes common scaling scenarios, including root partition, SWAP partition, and scaling a directory.
1. Root partition expansion
1.1 Standard partition expansion (OVF default)
This example is a CentOS 8 virtual machine, two disks, disk 1 capacity 60G for the root directory (including/boot), Disk 2 capacity 4G for SWAP.
(1) The status before expansion is as follows:
[root@sysin-c8 ~]# lsblk NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT sda 8:0 0 60G 0 disk └─sda1 8:1 0 60G 0 part / sdb 8:16 0 4G 0 disk └─sdb1 8:17 0 4G 0 part [SWAP] sr0 11:0 1 1024M 0 rom [root@sysin-c8 ~]# df -Th Filesystem Type Size Used Avail Use% Mounted on devtmpfs devtmpfs 386M 0 386M 0% /dev tmpfs tmpfs 400M 0 400M 0% /dev/shm tmpfs tmpfs 400M 11M 389M 3% /run tmpfs tmpfs 400M 0 400M 0% /sys/fs/cgroup /dev/sda1 xfs 60G 1.8G 59G 3% / tmpfs tmpfs 80M 0 80M 0% /run/user/0
(2) Expand the capacity of disk 1 in the virtual machine to 100G, and this process will not be taken.
If online addition is supported, you can refresh the disk status through the command:partprobe /dev/sda
(3) Start expanding the root directory:
[root@sysin-c8 ~]# fdisk /dev/sda Welcome to fdisk (util-linux 2.32.1). Changes will remain in memory only, until you decide to write them. Be careful before using the write command. Command (m for help):
(4) You can press m to view the help:
Command (m for help): m Help: DOS (MBR) a toggle a bootable flag b edit nested BSD disklabel c toggle the dos compatibility flag Generic d delete a partition F list free unpartitioned space l list known partition types n add a new partition p print the partition table t change a partition type v verify the partition table i print information about a partition Misc m print this menu u change display/entry units x extra functionality (experts only) Script I load disk layout from sfdisk script file O dump disk layout to sfdisk script file Save & Exit w write table to disk and exit q quit without saving changes Create a new label g create a new empty GPT partition table G create a new empty SGI (IRIX) partition table o create a new empty DOS partition table s create a new empty Sun partition table Command (m for help):
(5) Press p to view the partition on the current disk:
Command (m for help): p Disk /dev/sda: 100 GiB, 107374182400 bytes, 209715200 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 Disklabel type: dos Disk identifier: 0x7bb4c495 Device Boot Start End Sectors Size Id Type /dev/sda1 * 2048 125829119 125827072 60G 83 Linux # In this case, the disk is only one partition，Boot There is a bootable tag below *，/boot No separate partition
(6) Press d to delete/partition:
Command (m for help): d Selected partition 1 Partition 1 has been deleted. Command (m for help): # There is only one partition in this case，So deleted directly，If there are multiple partitions，It will prompt to enter the number to select
(7) Press n to create a new partition:
Command (m for help): n
Partition type
p primary (0 primary, 0 extended, 4 free)
e extended (container for logical partitions)
Select (default p): p #Select p primaryPartition number (1-4, default 1): #Directly enter the carriage default 1 i.e. sda1First sector (2048-209715199, default 2048): #Direct Enter the default value (sysin)Last sector, +sectors or +size{K,M,G,T,P} (2048-209715199, default 209715199): #Turn directly enter the default value, use all remaining space
Created a new partition 1 of type 'Linux' and of size 100 GiB.
Partition #1 contains a xfs signature.
Do you want to remove the signature? [Y]es/[N]o: N #Press N to keep the xfs signature. If removed, the UUID of the partition will change.
The signature will be removed by a write command.
Command (m for help):(8) Press p to view the status again:
Command (m for help): p Disk /dev/sda: 100 GiB, 107374182400 bytes, 209715200 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 Disklabel type: dos Disk identifier: 0x6a72cc03 Device Boot Start End Sectors Size Id Type /dev/sda1 2048 209715199 209713152 100G 83 Linux Filesystem/RAID signature on partition 1 will be wiped. Command (m for help):
(9) Important steps: Press a to set to boot:
This example/bootThere is no independent partition, you need to set boot flag. That is, the partition is set to bootable:
/bootThis step is not required for independent partitions.
Command (m for help): a Selected partition 1 The bootable flag on partition 1 is enabled now. # Press p to confirm again, there is a * symbol under BootCommand (m for help): p Disk /dev/sda: 100 GiB, 107374182400 bytes, 209715200 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 Disklabel type: dos Disk identifier: 0x6a72cc03 Device Boot Start End Sectors Size Id Type /dev/sda1 * 2048 209715199 209713152 100G 83 Linux Filesystem/RAID signature on partition 1 will be wiped. Command (m for help):
(10) Press w to save:
Command (m for help): w The partition table has been altered. Syncing disks.
(11) Important steps: Synchronize the capacity in the file system.
CentOS 7 starts using the xfs file system by default, using the xfs_growfs command to synchronize file system capacity.
If it is Ext4 (including 2 and 3), use the resize2fs command.
xfs_growfs / # Note xfs_growfs uses mountpoint#resize2fs /dev/sda1 # resize2fs Use device
(12) Confirm the partition results, you can restart the system to confirm whether it is normal
[root@sysin-c8 ~]# lsblk NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT sda 8:0 0 100G 0 disk └─sda1 8:1 0 100G 0 part / sdb 8:16 0 4G 0 disk └─sdb1 8:17 0 4G 0 part [SWAP] sr0 11:0 1 1024M 0 rom [root@sysin-c8 ~]# df -Th Filesystem Type Size Used Avail Use% Mounted on devtmpfs devtmpfs 386M 0 386M 0% /dev tmpfs tmpfs 400M 0 400M 0% /dev/shm tmpfs tmpfs 400M 11M 389M 3% /run tmpfs tmpfs 400M 0 400M 0% /sys/fs/cgroup /dev/sda1 xfs 100G 2.1G 98G 3% / tmpfs tmpfs 80M 0 80M 0% /run/user/0 [root@sysin-c8 ~]#
The expansion was successfully completed.
1.2 LVM partition expansion
LVM definition:
LVM (logical volume manager) Logical volume manager
It is mainly divided into these concepts:
- Physical volume - Physical volume PV
- Physical volumes are at the lowest level in the logical volume manager. Any logical volumes and volume groups must be established by physical volumes. The physical volume can be a complete hard disk or a partition in the hard disk.
- Volume group - Volume group VG
- A volume group is built on a physical volume, and a volume group can contain one or more physical volumes.
- Logical volume - Logical volume LV
- Logical volumes are similar to hard disk partitions in non-LVM systems, and a file system can be established on top of the logical volume (e.g.
/homeor/usrwait).
A process for establishing a logical volume is as follows: PV -> VG -> LV, the physical volume contains the volume group, and the volume group contains the logical volume.
This example is CentOS 7, a disk, independent/bootPartition, two LVM partitions, as follows:
# root @ C7-SYSIN in ~ [12:41:56] $ lsblk NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT sda 8:0 0 160G 0 disk ├─sda1 8:1 0 1G 0 part /boot └─sda2 8:2 0 159G 0 part ├─centos-root 253:0 0 155G 0 lvm / └─centos-swap 253:1 0 4G 0 lvm [SWAP] sr0 11:0 1 1024M 0 rom # root @ C7-SYSIN in ~ [12:41:56] $ df -Th Filesystem Type Size Used Avail Use% Mounted on /dev/mapper/centos-root xfs 155G 1.5G 154G 1% / 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/sda1 xfs 1014M 142M 873M 14% /boot tmpfs tmpfs 378M 0 378M 0% /run/user/0
Scales this virtual disk to 260G.
Note: You can also add a disk, which can simulate the addition of a physical disk, but the following disk letters are modified correspondingly "/dev/sda=/dev/sdb" and "/dev/sda3=/dev/sdb1".
(1) Create a partition
$ fdisk /dev/sda #Parallel to the original disk /dev/sdaWelcome 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.
Command (m for help): p #p View the current partition
Disk /dev/sda: 279.2 GB, 279172874240 bytes, 545259520 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: 0x000af364
Device Boot Start End Blocks Id System
/dev/sda1 * 2048 2099199 1048576 83 Linux
/dev/sda2 2099200 335544319 166722560 8e Linux LVM
Command (m for help): n #n Create a new partitionPartition type:
p primary (2 primary, 0 extended, 2 free)
e extended
Select (default p): p #p Main partitionPartition number (3,4, default 3): #Default order, enter directlyFirst sector (335544320-545259519, default 335544320): #Default direct returnUsing default value 335544320
Last sector, +sectors or +size{K,M,G} (335544320-545259519, default 545259519): #Default direct input to use all remaining spaceUsing default value 545259519
Partition 3 of type Linux and of size 100 GiB is set
Command (m for help): p #p Check the partition again
Disk /dev/sda: 279.2 GB, 279172874240 bytes, 545259520 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: 0x000af364
Device Boot Start End Blocks Id System
/dev/sda1 * 2048 2099199 1048576 83 Linux
/dev/sda2 2099200 335544319 166722560 8e Linux LVM
/dev/sda3 335544320 545259519 104857600 83 Linux
Command (m for help): w #w SaveThe partition table has been altered!
Calling ioctl() to re-read partition table.
WARNING: Re-reading the partition table failed with error 16: Device or resource busy.
The kernel still uses the old table. The new table will be used at
the next reboot or after you run partprobe(8) or kpartx(8)
Syncing disks.(2) Refresh the partition
# root @ C7-SYSIN in ~ [13:31:00] $ partprobe /dev/sda # root @ C7-SYSIN in ~ [13:31:54] $ lsblk NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT sda 8:0 0 260G 0 disk ├─sda1 8:1 0 1G 0 part /boot ├─sda2 8:2 0 159G 0 part │ ├─centos-root 253:0 0 155G 0 lvm / │ └─centos-swap 253:1 0 4G 0 lvm [SWAP] └─sda3 8:3 0 100G 0 part sr0 11:0 1 1024M 0 rom
(3) Create PV
$ pvcreate /dev/sda3 Physical volume "/dev/sda3" successfully created.
(4) View VG
$ vgdisplay --- Volume group --- VG Name centos System ID Format lvm2 Metadata Areas 1 Metadata Sequence No 3 VG Access read/write VG Status resizable MAX LV 0 Cur LV 2 Open LV 2 Max PV 0 Cur PV 1 Act PV 1 VG Size <159.00 GiB PE Size 4.00 MiB Total PE 40703 Alloc PE / Size 40703 / <159.00 GiB Free PE / Size 0 / 0 VG UUID Aul9M5-OJu8-3RB5-DU9Y-yi5m-ngyd-QyIKLw
VG name is centos
(5) Extended VG
Use /dev/sda3 PV to extend into centos VG.
$ vgextend centos /dev/sda3 Volume group "centos" successfully extended
(6) View LV
$ lvdisplay --- Logical volume --- LV Path /dev/centos/root LV Name root VG Name centos LV UUID ntq8LZ-qivt-B6ij-AZWi-97a9-H2Q5-YxznfS LV Write Access read/write LV Creation host, time localhost, 2021-08-22 14:12:50 +0800 LV Status available # open 1 LV Size <155.00 GiB Current LE 39679 Segments 1 Allocation inherit Read ahead sectors auto - currently set to 8192 Block device 253:0 --- Logical volume --- LV Path /dev/centos/swap LV Name swap VG Name centos LV UUID jvNgUR-KUsk-1hD4-h383-w3pc-OhBT-ZFMpyi LV Write Access read/write LV Creation host, time localhost, 2021-08-22 14:12:51 +0800 LV Status available # open 2 LV Size 4.00 GiB Current LE 1024 Segments 1 Allocation inherit Read ahead sectors auto - currently set to 8192 Block device 253:1
The root partition that needs to be extended is /dev/centos/root
(7) Expand the free space in VG to the root partition LV
$ lvextend -l +100%FREE /dev/centos/root Size of logical volume centos/root changed from <155.00 GiB (39679 extents) to 254.99 GiB (65278 extents). Logical volume centos/root successfully resized.
(8) Refresh the root partition
If it is an ext4 file system (including 2 and 3), use the resize2fs command.
xfs_growfs /dev/centos/root
(9) Verification results
# root @ C7-SYSIN in ~ [13:39:53] $ lsblk NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT sda 8:0 0 260G 0 disk ├─sda1 8:1 0 1G 0 part /boot ├─sda2 8:2 0 159G 0 part │ ├─centos-root 253:0 0 255G 0 lvm / │ └─centos-swap 253:1 0 4G 0 lvm [SWAP] └─sda3 8:3 0 100G 0 part └─centos-root 253:0 0 255G 0 lvm / sr0 11:0 1 1024M 0 rom # root @ C7-SYSIN in ~ [13:39:53] $ df -Th Filesystem Type Size Used Avail Use% Mounted on /dev/mapper/centos-root xfs 255G 1.5G 254G 1% / 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/sda1 xfs 1014M 142M 873M 14% /boot tmpfs tmpfs 378M 0 378M 0% /run/user/0
You can see that the root directory capacity expansion is successful.
2. SWAP partition expansion
2.1 Create a file as a SWAP partition (OVF default in this site)
This is the easiest way to create a file directly in the / directory as a swap partition, which can be very flexible and perfect to enable and disable swap and resize online.
(1) Create the file to be used as swap partition:
If you increase the 4GB size swap partition, the command is written as follows, where count is equal to the desired number of blocks (bs*count = file size).
# Here is defined as /dd if=/dev/zero of=/ bs=1M count=4096 # Modify permissionschmod 600 /
(2) Create a SWAP partition file system:
mkswap / #mkswap - set up a Linux swap area
(3) Enable swap partition files:
swapon / #Enable swap document
Used at this timefree -mThe command shows that the capacity of Swap is equal to the sum of the original capacity plus the above-mentioned created file capacity.
(4) Edit/etc/fstabAutomatically load the above swap file on the startup:
Add the following line.
/ none swap defaults 0 0 # The second field uses swap by default in CentOS, and the two are not different./ swap swap defaults 0 0 # About the style of the field，use tab Or spaces are OK，No quantity requirement，通常为了对齐use多个空格
Direct command to add:
sudo sh -c "echo '/ none swap defaults 0 0' >> /etc/fstab"
(5) Cancel the swap file
swapoff / rm -r /
Then edit/etc/fstab, just delete the above added line.
Used by default in Ubuntu 20.04/As a SWAP partition, you can swapoff directly and delete the original file, and then recreate the file with the same name to simply expand the capacity. We have borrowed from Ubuntu's practices here and recommend this method.
2.2 Standard partition SWAP capacity expansion
This example is a CentOS 8 virtual machine, two disks, disk 1 capacity 60G for the root directory (including/boot), Disk 2 capacity 4G for SWAP.
(1) The status before expansion is as follows:
[root@sysin-c8 ~]# lsblk NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT sda 8:0 0 60G 0 disk └─sda1 8:1 0 60G 0 part / sdb 8:16 0 4G 0 disk └─sdb1 8:17 0 4G 0 part [SWAP] sr0 11:0 1 1024M 0 rom [root@sysin-c8 ~]# df -Th Filesystem Type Size Used Avail Use% Mounted on devtmpfs devtmpfs 386M 0 386M 0% /dev tmpfs tmpfs 400M 0 400M 0% /dev/shm tmpfs tmpfs 400M 11M 389M 3% /run tmpfs tmpfs 400M 0 400M 0% /sys/fs/cgroup /dev/sda1 xfs 60G 1.8G 59G 3% / tmpfs tmpfs 80M 0 80M 0% /run/user/0
(2) Expand the capacity of disk 2 in the virtual machine to 16G, and this process will not be taken.
Refresh disk status:partprobe /dev/sdb
(3) Close swap
swapoff /dev/sdb1
(4) Recreate/dev/sdb1Partition
[root@sysin-c8 ~]# fdisk /dev/sdb #Select /dev/sdb
Welcome to fdisk (util-linux 2.32.1).
Changes will remain in memory only, until you decide to write them.
Be careful before using the write command.
Command (m for help): p #View the partition of courseDisk /dev/sdb: 16 GiB, 17179869184 bytes, 33554432 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
Disklabel type: dos
Disk identifier: 0x316023cd
Device Boot Start End Sectors Size Id Type
/dev/sdb1 2048 8388607 8386560 4G 82 Linux swap / Solaris
Command (m for help): d #Delete the partition, only one partition will not prompt to select the numberSelected partition 1
Partition 1 has been deleted.
Command (m for help): n #Create a new partitionPartition type
p primary (0 primary, 0 extended, 4 free)
e extended (container for logical partitions)
Select (default p): p #Main partition, enter P or enter directlyPartition number (1-4, default 1): #Enter directly in order 1First sector (2048-33554431, default 2048): #Enter it directlyLast sector, +sectors or +size{K,M,G,T,P} (2048-33554431, default 33554431): #Enter it directly to use all available space
Created a new partition 1 of type 'Linux' and of size 16 GiB.
Partition #1 contains a swap signature.
Do you want to remove the signature? [Y]es/[N]o: N # Select N Do not remove the swap signature, the disk UUID remains unchanged
The signature will be removed by a write command.
Command (m for help): t #Change partition typeSelected partition 1
Hex code (type L to list all codes): L #Enter L to view available codes
0 Empty 24 NEC DOS 81 Minix / old Lin bf Solaris
1 FAT12 27 Hidden NTFS Win 82 Linux swap / So c1 DRDOS/sec (FAT-
2 XENIX root 39 Plan 9 83 Linux c4 DRDOS/sec (FAT-
3 XENIX usr 3c PartitionMagic 84 OS/2 hidden or c6 DRDOS/sec (FAT-
4 FAT16 <32M 40 Venix 80286 85 Linux extended c7 Syrinx
5 Extended 41 PPC PReP Boot 86 NTFS volume set da Non-FS data
6 FAT16 42 SFS 87 NTFS volume set db CP/M / CTOS / .
7 HPFS/NTFS/exFAT 4d 88 Linux plaintext de Dell Utility
8 AIX 4e 2nd part 8e Linux LVM df BootIt
9 AIX bootable 4f 3rd part 93 Amoeba e1 DOS access
a OS/2 Boot Manag 50 OnTrack DM 94 Amoeba BBT e3 DOS R/O
b W95 FAT32 51 OnTrack DM6 Aux 9f BSD/OS e4 SpeedStor
c W95 FAT32 (LBA) 52 CP/M a0 IBM Thinkpad hi ea Rufus alignment
e W95 FAT16 (LBA) 53 OnTrack DM6 Aux a5 FreeBSD eb BeOS fs
f W95 Ext'd (LBA) 54 OnTrackDM6 a6 OpenBSD ee GPT
10 OPUS 55 EZ-Drive a7 NeXTSTEP ef EFI (FAT-12/16/
11 Hidden FAT12 56 Golden Bow a8 Darwin UFS f0 Linux/PA-RISC b
12 Compaq diagnost 5c Priam Edisk a9 NetBSD f1 SpeedStor
14 Hidden FAT16 <3 61 SpeedStor ab Darwin boot f4 SpeedStor
16 Hidden FAT16 63 GNU HURD or Sys af HFS / HFS+ f2 DOS secondary
17 Hidden HPFS/NTF 64 Novell Netware b7 BSDI fs fb VMware VMFS
18 AST SmartSleep 65 Novell Netware b8 BSDI swap fc VMware VMKCORE
1b Hidden W95 FAT3 70 DiskSecure Mult bb Boot Wizard hid fd Linux raid auto
1c Hidden W95 FAT3 75 PC/IX bc Acronis FAT32 L fe LANstep
1e Hidden W95 FAT1 80 Old Minix be Solaris boot ff BBT
Hex code (type L to list all codes): 82 #Enter 82, change to SWAPChanged type of partition 'Linux' to 'Linux swap / Solaris'.
Command (m for help): p # Check the partition again, it is already swapDisk /dev/sdb: 16 GiB, 17179869184 bytes, 33554432 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
Disklabel type: dos
Disk identifier: 0x316023cd
Device Boot Start End Sectors Size Id Type
/dev/sdb1 2048 33554431 33552384 16G 82 Linux swap / Solaris
Filesystem/RAID signature on partition 1 will be wiped.
Command (m for help): w #Save ExitThe partition table has been altered.
Calling ioctl() to re-read partition table.
Re-reading the partition table failed.: Device or resource busy
The kernel still uses the old table. The new table will be used at the next reboot or after you run partprobe(8) or kpartx(8).Finally, the prompt needs to restart or run the partprobe and kpartx commands to take effect. Execute the command here:partprobe /dev/sdb1。
The author reported an error by executing the partprobe command in a test. It may be that the swap signature was removed during the partitioning process, the UUID of the partition was changed, and it was restarted directly. It took a while before entering the system, but it did not affect normal operation.
(5) Create a swap file system
mkswap /dev/sdb1 # The prompt is as followsSetting up swapspace version 1, size = 16 GiB (17178816512 bytes) no label, UUID=df11dbb4-9665-4732-b865-03913713fa5e # Pay attention to the UUID change，Need to be modified and replaced /etc/fstab
(6) Open swap
swapon /dev/sdb1
(7) Change/etc/fstab
If the swap signature is removed during the recreation of the partition, the disk UUID changes and needs to be edited/etc/fstabMake corresponding changes.
Even if the swap signature is not removed, the UUID has changed after using the mkswap command and needs to be edited./etc/fstabMake corresponding changes.
To view the UUID of the partition Use the commandblkidorlsblk -f。
#UUID=c154479a-28e1-40b2-b10c-646b41693f51 swap swap defaults 0 0 #OriginalUUID=df11dbb4-9665-4732-b865-03913713fa5e swap swap defaults 0 0
Of course, you can also create additional partitions as additional swap partitions. The original swap partition remains unchanged. Finally, edit/etc/fstabIt can be loaded automatically.
(8) Change/etc/default/grub
There is a resume option in the grub configuration file, pointing to the swap partition. If the standard partition uses the UUID of the swap partition by default.
vi /etc/default/grub # Find the following lineGRUB_CMDLINE_LINUX="crashkernel=auto resume=UUID=c154479a-28e1-40b2-b10c-646b41693f51 rhgb quiet" #original# Modify as followsGRUB_CMDLINE_LINUX="crashkernel=auto resume=UUID=df11dbb4-9665-4732-b865-03913713fa5e rhgb quiet" # Rebuild the configurationgrub2-mkconfig -o /boot/grub2/ # UEFI boot mode: #grub2-mkconfig -o /boot/efi/EFI/redhat/
2.3 LVM SWAP capacity expansion
This example is CentOS 7, a disk, independent/bootPartition, two LVM partitions, as follows:
# root @ C7-SYSIN in ~ [12:41:56] $ lsblk NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT sda 8:0 0 160G 0 disk ├─sda1 8:1 0 1G 0 part /boot └─sda2 8:2 0 159G 0 part ├─centos-root 253:0 0 155G 0 lvm / └─centos-swap 253:1 0 4G 0 lvm [SWAP] sr0 11:0 1 1024M 0 rom # root @ C7-SYSIN in ~ [12:41:56] $ df -Th Filesystem Type Size Used Avail Use% Mounted on /dev/mapper/centos-root xfs 155G 1.5G 154G 1% / 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/sda1 xfs 1014M 142M 873M 14% /boot tmpfs tmpfs 378M 0 378M 0% /run/user/0
Increase this virtual disk capacity by 12G.
Note: You can also add a disk, which can simulate the addition of a physical disk, but the following disk letters are modified correspondingly "/dev/sda=/dev/sdb" and "/dev/sda3=/dev/sdb1".
(1) Close swap
Check/etc/fstabYou can see the LV name of swap:
$ cat /etc/fstab | grep swap /dev/mapper/centos-swap swap swap defaults 0 0
Close it:
swapoff /dev/mapper/centos-swap
(2) Create a partition
$ fdisk /dev/sda #The original disk /dev/sda partition can also be a newly added disk. The operation method is the same when using /dev/sdb in order.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.
Command (m for help): p #View the current partition
Disk /dev/sda: 184.7 GB, 184683593728 bytes, 360710144 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: 0x000af364
Device Boot Start End Blocks Id System
/dev/sda1 * 2048 2099199 1048576 83 Linux
/dev/sda2 2099200 335544319 166722560 8e Linux LVM
Command (m for help): n #Create a new partitionPartition type:
p primary (2 primary, 0 extended, 2 free)
e extended
Select (default p): #Enter it directly, default main partitionUsing default response p
Partition number (3,4, default 3): #Direct Enter in order by default 3First sector (335544320-360710143, default 335544320): #Enter it directlyUsing default value 335544320
Last sector, +sectors or +size{K,M,G} (335544320-360710143, default 360710143): #Enter it directly, use all remaining spaceUsing default value 360710143
Partition 3 of type Linux and of size 12 GiB is set #12G That's right
Command (m for help): p #View partition again
Disk /dev/sda: 184.7 GB, 184683593728 bytes, 360710144 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: 0x000af364
Device Boot Start End Blocks Id System
/dev/sda1 * 2048 2099199 1048576 83 Linux
/dev/sda2 2099200 335544319 166722560 8e Linux LVM
/dev/sda3 335544320 360710143 12582912 83 Linux
Command (m for help): w #Save ExitThe partition table has been altered!
Calling ioctl() to re-read partition table.
WARNING: Re-reading the partition table failed with error 16: Device or resource busy.
The kernel still uses the old table. The new table will be used at
the next reboot or after you run partprobe(8) or kpartx(8)
Syncing disks.
You have new mail.(3) Refresh the partition
# root @ C7-SYSIN in ~ [13:31:00] $ partprobe /dev/sda # root @ C7-SYSIN in ~ [13:31:54] $ lsblk NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT sda 8:0 0 172G 0 disk ├─sda1 8:1 0 1G 0 part /boot ├─sda2 8:2 0 159G 0 part │ ├─centos-root 253:0 0 155G 0 lvm / │ └─centos-swap 253:1 0 4G 0 lvm └─sda3 8:3 0 12G 0 part sr0 11:0 1 1024M 0 rom
(4) Create PV
$ pvcreate /dev/sda3 Physical volume "/dev/sda3" successfully created.
(5) View VG
$ vgdisplay --- Volume group --- VG Name centos System ID Format lvm2 Metadata Areas 1 Metadata Sequence No 3 VG Access read/write VG Status resizable MAX LV 0 Cur LV 2 Open LV 2 Max PV 0 Cur PV 1 Act PV 1 VG Size <159.00 GiB PE Size 4.00 MiB Total PE 40703 Alloc PE / Size 40703 / <159.00 GiB Free PE / Size 0 / 0 VG UUID Aul9M5-OJu8-3RB5-DU9Y-yi5m-ngyd-QyIKLw
VG name is centos
(6) Extended VG
Use /dev/sda3 PV to extend into centos VG.
$ vgextend centos /dev/sda3 Volume group "centos" successfully extended
(7) View LV
$ lvdisplay --- Logical volume --- LV Path /dev/centos/root LV Name root VG Name centos LV UUID ntq8LZ-qivt-B6ij-AZWi-97a9-H2Q5-YxznfS LV Write Access read/write LV Creation host, time localhost, 2021-08-22 14:12:50 +0800 LV Status available # open 1 LV Size <155.00 GiB Current LE 39679 Segments 1 Allocation inherit Read ahead sectors auto - currently set to 8192 Block device 253:0 --- Logical volume --- LV Path /dev/centos/swap LV Name swap VG Name centos LV UUID jvNgUR-KUsk-1hD4-h383-w3pc-OhBT-ZFMpyi LV Write Access read/write LV Creation host, time localhost, 2021-08-22 14:12:51 +0800 LV Status available # open 2 LV Size 4.00 GiB Current LE 1024 Segments 1 Allocation inherit Read ahead sectors auto - currently set to 8192 Block device 253:1
The root partition that needs to be extended is /dev/centos/swap
(8) Expand the free space in VG to the root partition LV
$ lvextend -l +100%FREE /dev/centos/swap Size of logical volume centos/swap changed from 4.00 GiB (1024 extents) to <16.00 GiB (4095 extents). Logical volume centos/swap successfully resized.
(9) Refresh the swap partition
partprobe /dev/centos/swap
(10) Verification results
# root @ C7-SYSIN in ~ [15:54:13] $ lsblk NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT sda 8:0 0 172G 0 disk ├─sda1 8:1 0 1G 0 part /boot ├─sda2 8:2 0 159G 0 part │ ├─centos-root 253:0 0 155G 0 lvm / │ └─centos-swap 253:1 0 16G 0 lvm └─sda3 8:3 0 12G 0 part └─centos-swap 253:1 0 16G 0 lvm sr0 11:0 1 1024M 0 rom # root @ C7-SYSIN in ~ [15:54:13] $ df -Th Filesystem Type Size Used Avail Use% Mounted on /dev/mapper/centos-root xfs 155G 1.5G 154G 1% / 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/sda1 xfs 1014M 142M 873M 14% /boot tmpfs tmpfs 378M 0 378M 0% /run/user/0
You can see that the root directory capacity expansion is successful.
(11) Create a swap file system
$ mkswap /dev/mapper/centos-swap mkswap: /dev/mapper/centos-swap: warning: wiping old swap signature. Setting up swapspace version 1, size = 16773116 KiB no label, UUID=fb85ef4d-59aa-4554-a3bd-b4cc37746c51
(12) Turn on swap
swapon /dev/mapper/centos-swap
usefree -mYou can see that the swap partition capacity has successfully changed to 16G./etc/fstabNo modification is required.
3. Mount the new disk to the new partition
This example uses Ubuntu 20.04, and the partition is as follows. We have added a 100G disk and mounted as/data, and add a 100G disk to replace the original one/varDirectory (assuming that the original disk partition is not enough). Of course, we can also directly expand the root partition and refer to the above description in this article. Here we create separate/dataand/varPartition.
Create a standalone/dataand/varPartitioning can also be done using LVM. The specific operations are different but the logical steps are the same. You can refer to other articles. This article uses standard partitions.
$ lsblk NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT sda 8:0 0 160G 0 disk ├─sda1 8:1 0 1M 0 part ├─sda2 8:2 0 1G 0 part /boot └─sda3 8:3 0 159G 0 part └─ubuntu--vg-ubuntu--lv 253:0 0 159G 0 lvm / sr0 11:0 1 1024M 0 rom # sa @ U20 in ~ [16:14:05] $ df -Th Filesystem Type Size Used Avail Use% Mounted on udev devtmpfs 1.9G 0 1.9G 0% /dev tmpfs tmpfs 391M 1.1M 390M 1% /run /dev/mapper/ubuntu--vg-ubuntu--lv ext4 156G 6.0G 142G 5% / tmpfs tmpfs 2.0G 0 2.0G 0% /dev/shm tmpfs tmpfs 5.0M 0 5.0M 0% /run/lock tmpfs tmpfs 2.0G 0 2.0G 0% /sys/fs/cgroup /dev/sda2 ext4 976M 103M 806M 12% /boot tmpfs tmpfs 391M 0 391M 0% /run/user/1000
Ubuntu is quite special. There is a 1M partition here that is bios_grub, which will be automatically created whether using LVM or standard partitions.
After adding a new hard disk, as follows: If you cannot see the new disk, you need to restart or execute the partprobe command.
$ lsblk NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT sda 8:0 0 160G 0 disk ├─sda1 8:1 0 1M 0 part ├─sda2 8:2 0 1G 0 part /boot └─sda3 8:3 0 159G 0 part └─ubuntu--vg-ubuntu--lv 253:0 0 159G 0 lvm / sdb 8:16 0 100G 0 disk sdc 8:32 0 100G 0 disk sr0 11:0 1 1024M 0 rom
3.1 Mount the disk as a new directory
(1) Create a partition
# sa @ U20 in ~ [16:23:43] C:1
$ sudo fdisk /dev/sdb #Create /dev/sdb partition[sudo] password for sa:
Welcome to fdisk (util-linux 2.34).
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.
Created a new DOS disklabel with disk identifier 0x9a7ae73a.
Command (m for help): n #n Create a new partitionPartition type
p primary (0 primary, 0 extended, 4 free)
e extended (container for logical partitions)
Select (default p): #Enter it directly, main partition
Using default response p.
Partition number (1-4, default 1): #Enter directly, number in order 1First sector (2048-209715199, default 2048): #Enter it directlyLast sector, +/-sectors or +/-size{K,M,G,T,P} (2048-209715199, default 209715199): #Enter it directly, use all available space
Created a new partition 1 of type 'Linux' and of size 100 GiB.
Command (m for help): p #View partitionDisk /dev/sdb: 100 GiB, 107374182400 bytes, 209715200 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: 0x9a7ae73a
Device Boot Start End Sectors Size Id Type
/dev/sdb1 2048 209715199 209713152 100G 83 Linux
Command (m for help): w #Save ExitThe partition table has been altered.
Calling ioctl() to re-read partition table.
Syncing disks.(2) Create a file system (format the partition)
sudo mkfs -t ext4 /dev/sdb1 # The above use ext4，Can also be used xfs
(3) Mount to/dataTable of contents
sudo mkdir /data sudo mount /dev/sdb1 /data
(4) Automatic loading on the computer
edit/etc/fstab, add the following line:
/dev/sdb1 /data ext4 defaults 0 0
(5) Verification
After restarting, check whether it loaded correctly:
$ df -Th Filesystem Type Size Used Avail Use% Mounted on udev devtmpfs 1.9G 0 1.9G 0% /dev tmpfs tmpfs 391M 1.2M 390M 1% /run /dev/mapper/ubuntu--vg-ubuntu--lv ext4 156G 6.0G 142G 5% / tmpfs tmpfs 2.0G 0 2.0G 0% /dev/shm tmpfs tmpfs 5.0M 0 5.0M 0% /run/lock tmpfs tmpfs 2.0G 0 2.0G 0% /sys/fs/cgroup /dev/sda2 ext4 976M 103M 806M 12% /boot tmpfs tmpfs 391M 0 391M 0% /run/user/1000 /dev/sdb1 ext4 98G 61M 93G 1% /data
3.2 Mount the disk in the original directory
(1) Create a partition
# sa @ U20 in ~ [16:23:43] C:1
$ sudo fdisk /dev/sdc #Create /dev/sdc partition[sudo] password for sa:
Welcome to fdisk (util-linux 2.34).
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.
Created a new DOS disklabel with disk identifier 0x9a7ae73a.
Command (m for help): n #n Create a new partitionPartition type
p primary (0 primary, 0 extended, 4 free)
e extended (container for logical partitions)
Select (default p): #Enter it directly, main partition
Using default response p.
Partition number (1-4, default 1): #Enter directly, number in order 1First sector (2048-209715199, default 2048): #Enter it directlyLast sector, +/-sectors or +/-size{K,M,G,T,P} (2048-209715199, default 209715199): #Enter it directly, use all available space
Created a new partition 1 of type 'Linux' and of size 100 GiB.
Command (m for help): p #View partitionDisk /dev/sdc: 100 GiB, 107374182400 bytes, 209715200 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: 0x9a7ae73a
Device Boot Start End Sectors Size Id Type
/dev/sdc1 2048 209715199 209713152 100G 83 Linux
Command (m for help): w #Save ExitThe partition table has been altered.
Calling ioctl() to re-read partition table.
Syncing disks.(2) Create a file system (format the partition)
sudo mkfs -t xfs /dev/sdc1 # The above use xfs，Can also be used ext4
(3) Mount to/varnewTable of contents
sudo mkdir /varnew sudo mount /dev/sdc1 /varnew
(4) Key steps: copy/varAll contents under it to the new hard drive
sudo cp -a /var/** /varnew
Definition:
The "-a" option is equivalent to the "-d, -p, -r" option. When using the "-a" option, all attributes of the target file and the source file are consistent, including the owner of the source file, group, time and soft linkability.
Two "**" are used here to ensure that if Bash is enabledGlobstarAll files can be copied after the option.
(5) Rename the current one/varDirectory (optional, can also be deleted directly)
sudo mv /var /varold
(6) Remount the hard drive to/varTable of contents
sudo umount /dev/sdc1 sudo mkdir /var sudo mount /dev/sdc1 /var
(7) Set up automatic mount on startup
#sudo vi /etc/fstab #Add a line at the end of the file/dev/sdc1 /var xfs defaults 0 0
(8) Delete the original/varTable of contents
After confirming that there is no problem, completely delete the original one/var
sudo rm -rf /varold
4. Summary
Using standard partition expansion seems to be easier than LVM, especially in virtual machine environments, virtual disks can directly expand capacity and do not require the use of LVM features.
In the physical machine environment, adding physical disk capacity expansion will give full play to the advantages of using LVM.
Therefore, it is recommended to use standard partitions in virtual machines or cloud environments (independent swap virtual disks or swap files are more convenient). Physical machines, especially application scenarios with large data volumes, you can consider prioritizing the use of LVM.
5. Attached
Comparison of MBR and GPT
| category | Main boot method | Number of primary partitions | Maximum capacity | How many bits of systems are supported | Partition method |
|---|---|---|---|---|---|
| MBR | BIOS+MBR | 4 | 2T | 32 and 64 | fdisk |
| GPT | UEFI+GPT | 128 | 18EB（1EB=1024PB=1048576TB） | 64 | parted |
Parted partitioning and creating logical volume LVM
When partitioning a hard disk larger than 2TB, fdisk is no longer applicable and requires using parted to partition the hard disk.
Parted partitioning process:
parted -l #View all disk statusparted /dev/vdb #Create partitions larger than 2T through parted toolmklabel gpt #Create a disk tagmkpart primary 0% 100% #Create the entire partitionq #quit #Other commands------------------- (parted) mklabel #Create a disk tagNew disk labeltype? gpt (parted) p #View partition status(parted) mkpart Partition name? []? gpt2t #Specify the partition nameFile system type? [ext2]ext3 #Specify partition typeStart? 1 #Specify the start positionEnd? 2190GB #Specify the end position(parted) P #Display partition information(parted) Q #quit
The process of creating a logical volume
fdiks -l #View partitionpvcreate /dev/vdb1 #Create a pv physical volumevgcreate vgdata /dev/vdb1 #Create a vg volume grouplvcreate -l +100%FREE -n lvdata vgdata #Create lv logical volume /dev/mapper/vgdata-lvdata #Format logical volumemkdir /data #Create a data foldermount /dev/mapper/vgdata-lvdata /data #mount logical volumes to /datavim /etc/fastab #Add to boot up/dev/mapper/vgdata-lvdata /data xfs defaults 0 0 mount -a #Check the mount
Summarize
The above is personal experience. I hope you can give you a reference and I hope you can support me more.