Tutorial on adjusting the size of lvm logical volume partition in Linux (for different file systems such as xfs and ext4)
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Preface When we installed the system, we did not allocate the partition space properly. During the subsequent maintenance process, we found that some partitions had insufficient space, while some partitions had a lot of remaining space. If these partitions use lvm when installing the system (provided that these partitions are lvm logical volume partitions), then they can be easily expanded or reduced! Different file system types have different creation, checking, and adjustment commands. The following is a record of the expansion and reduction operations of the lvm partition space of the xfs and ext2/3/4 file systems: ------------------------------------------------------------------------------------------ Of particular note:
------------------------------------------------------------------------------------------ 1) The resize command for ext2/ext3/ext4 file systems is resize2fs (both increasing and decreasing are supported) lvextend -L 120G /dev/mapper/centos-home //Increase to 120G lvextend -L +20G /dev/mapper/centos-home //Increase 20G lvreduce -L 50G /dev/mapper/centos-home //Reduce to 50G lvreduce -L -8G /dev/mapper/centos-home //Reduce 8G resize2fs /dev/mapper/centos-home //Execute adjustment 2) The xfs file system adjustment command is xfs_growfs (only supports growth) lvextend -L 120G /dev/mapper/centos-home //Increase to 120G lvextend -L +20G /dev/mapper/centos-home //Increase 20G xfs_growfs /dev/mapper/centos-home //Execute adjustment That is to say: the xfs file system only supports increasing the partition space, but not reducing it (remember this! ... If you insist on reducing it, you can only reformat the logical partition using the mkfs.xfs command after reducing it before mounting it. In this case, the original data on the logical partition will be lost. If there are important documents, then take a break. Example 1 (when there is free space on the system) 1) Check the partition space. As shown below, it is an xfs file system (the -T parameter of df can show the file format). [root@localhost ~]# df -hT File system type Capacity Used Available Used% Mount point /dev/mapper/centos-root xfs 200G 2.2G 198G 2% / devtmpfs devtmpfs 32G 0 32G 0% /dev tmpfs tmpfs 32G 0 32G 0% /dev/shm tmpfs tmpfs 32G 49M 32G 1% /run tmpfs tmpfs 32G 0 32G 0% /sys/fs/cgroup /dev/sda1 xfs 197M 139M 59M 71% /boot tmpfs tmpfs 6.3G 0 6.3G 0% /run/user/0 /dev/mapper/centos-home xfs 628G 33M 718G 1% /home 2) Use the vgdisplay command to view the free space on the system root@localhost ~]# vgdisplay --- Volume group --- VG Name centos System ID Format lvm2 Metadata Areas 1 Metadata Sequence No 6 VG Access read/write VG Status resizable MAX LV 0 Cur LV 3 Open LV 3 Max PV 0 Cur PV 1 Act PV 1 VG Size 930.80 GiB PE Size 4.00 MiB Total PE 238285 Alloc PE / Size 212736 / 831.00 GiB Free PE / Size 25549 / 99.80 GiB //This item indicates that there is 99.80G of free space on the system (25549) VG UUID a5hiAh-LB8M-9lRv-Ps1a-z35L-J4fk-sP3KrF 3) Add or subtract the 90GB of free space found above to the /home partition [root@localhost ~]# lvextend -L +90G /dev/mapper/centos-home //Or use the -l parameter (with the number of PEs), i.e. lvextend -l +25500 /dev/mapper/centos-home Size of logical volume centos/home changed from 628.00 GiB (160768 extents) to 718.00 GiB (183808 extents). Logical volume centos/home successfully resized. [root@localhost ~]# xfs_growfs /dev/mapper/centos-home meta-data=/dev/mapper/centos-home isize=512 agcount=4, agsize=41156608 blks = sectsz=512 attr=2, projid32bit=1 = crc=1 finobt=0 spinodes=0 data = bsize=4096 blocks=164626432, imaxpct=25 = sunit=0 swidth=0 blks naming =version 2 bsize=4096 ascii-ci=0 ftype=1 log =internal bsize=4096 blocks=80384, version=2 = sectsz=512 sunit=0 blks, lazy-count=1 realtime =none extsz=4096 blocks=0, rtextents=0 data blocks changed from 164626432 to 188219392 4) Looking at the system partition again, I found that the home partition has been increased by 90G (after this method of increase, the previous data in the home partition will not be lost) [root@localhost ~]# df -h File system capacity used Available used% Mount point /dev/mapper/centos-root 200G 2.2G 198G 2% / devtmpfs 32G 0 32G 0% /dev tmpfs 32G 0 32G 0% /dev/shm tmpfs 32G 49M 32G 1% /run tmpfs 32G 0 32G 0% /sys/fs/cgroup /dev/sda1 197M 139M 59M 71% /boot tmpfs 6.3G 0 6.3G 0% /run/user/0 /dev/mapper/centos-home 718G 33M 718G 1% /home Although the xfs file system only supports increase, not decrease. But it does not mean that the file cannot be reduced under the xfs system file, but after reducing it, it needs to be reformatted before it can be mounted. In this way, the original data is lost! Example 2: This situation only applies to the case where the system has just been installed and there is no data in the logical partition or the data is small and unimportant and can be deleted or copied. After the system is installed, I find that the home partition is too large, and I want to take out 100G from the home partition to the / partition [root@localhost ~]# df -hT File system type Capacity Used Available Used% Mount point /dev/mapper/centos-root xfs 205G 2.2G 203G 2% / devtmpfs devtmpfs 32G 0 32G 0% /dev tmpfs tmpfs 32G 0 32G 0% /dev/shm tmpfs tmpfs 32G 49M 32G 1% /run tmpfs tmpfs 32G 0 32G 0% /sys/fs/cgroup /dev/sda1 xfs 197M 139M 59M 71% /boot tmpfs tmpfs 6.3G 0 6.3G 0% /run/user/0 /dev/mapper/centos-home xfs 718G 33M 718G 1% /home [root@localhost ~]# umount /home/ [root@localhost ~]# lvreduce -L -100G /dev/mapper/centos-home WARNING: Reducing active logical volume to 618.00 GiB. THIS MAY DESTROY YOUR DATA (filesystem etc.) Do you really want to reduce centos/home? [y/n]: y Size of logical volume centos/home changed from 718.00 GiB (183808 extents) to 618.00 GiB (158208 extents). Logical volume centos/home successfully resized. As shown below, it is clear that the xfs file system cannot perform partition reduction adjustments! [root@localhost ~]# xfs_growfs /dev/mapper/centos-home xfs_growfs: /dev/mapper/centos-home is not a mounted XFS filesystem [root@localhost ~]# mount /dev/mapper/centos-home /home/ mount: /dev/mapper/centos-home: cannot read superblock In this case, you can only re-format the partition and then mount it under home again. [root@localhost ~]# mkfs.xfs /dev/mapper/centos-home -f meta-data=/dev/mapper/centos-home isize=512 agcount=4, agsize=41156608 blks = sectsz=512 attr=2, projid32bit=1 = crc=1 finobt=0, sparse=0 data = bsize=4096 blocks=164626432, imaxpct=25 = sunit=0 swidth=0 blks naming =version 2 bsize=4096 ascii-ci=0 ftype=1 log =internal log bsize=4096 blocks=80384, version=2 = sectsz=512 sunit=0 blks, lazy-count=1 realtime =none extsz=4096 blocks=0, rtextents=0 [root@localhost ~]# mount /dev/mapper/centos-home /home/ Checking the partitions again, I found that the home partition had been reduced by 100G, but all the previous data in this partition was gone. [root@localhost ~]# df -hT File system type Capacity Used Available Used% Mount point /dev/mapper/centos-root xfs 205G 2.2G 203G 2% / devtmpfs devtmpfs 32G 0 32G 0% /dev tmpfs tmpfs 32G 0 32G 0% /dev/shm tmpfs tmpfs 32G 49M 32G 1% /run tmpfs tmpfs 32G 0 32G 0% /sys/fs/cgroup /dev/sda1 xfs 197M 139M 59M 71% /boot tmpfs tmpfs 6.3G 0 6.3G 0% /run/user/0 /dev/mapper/centos-home xfs 618G 73M 578G 1% /home --------------------------------------------------------------------------- When reformatting above, you can also format this as ext4. [root@localhost ~]# mkfs.ext4 /dev/mapper/centos-home [root@localhost ~]# cat /etc/fstab //Change the xfs in the boot mount setting of the home partition to ext4 --------------------------------------------------------------------------- Then put the 100G taken from the home partition into the / partition [root@localhost ~]# vgdisplay --- Volume group --- VG Name centos System ID Format lvm2 Metadata Areas 1 Metadata Sequence No 9 VG Access read/write VG Status resizable MAX LV 0 Cur LV 3 Open LV 3 Max PV 0 Cur PV 1 Act PV 1 VG Size 930.80 GiB PE Size 4.00 MiB Total PE 238285 Alloc PE / Size 211456 / 826.00 GiB Free PE / Size 26829 / 104.80 GiB VG UUID a5hiAh-LB8M-9lRv-Ps1a-z35L-J4fk-sP3KrF [root@localhost ~]# lvextend -L +100G /dev/mapper/centos-root Size of logical volume centos/root changed from 205.00 GiB (52480 extents) to 305.00 GiB (78080 extents). Logical volume centos/root successfully resized. [root@localhost ~]# xfs_growfs /dev/mapper/centos-root meta-data=/dev/mapper/centos-root isize=256 agcount=5, agsize=13107200 blks = sectsz=512 attr=2, projid32bit=1 = crc=0 finobt=0 spinodes=0 data = bsize=4096 blocks=53739520, imaxpct=25 = sunit=0 swidth=0 blks naming =version 2 bsize=4096 ascii-ci=0 ftype=0 log =internal bsize=4096 blocks=25600, version=2 = sectsz=512 sunit=0 blks, lazy-count=1 realtime =none extsz=4096 blocks=0, rtextents=0 data blocks changed from 53739520 to 79953920 [root@localhost ~]# df -hT File system type Capacity Used Available Used% Mount point /dev/mapper/centos-root xfs 305G 2.2G 203G 2% / devtmpfs devtmpfs 32G 0 32G 0% /dev tmpfs tmpfs 32G 0 32G 0% /dev/shm tmpfs tmpfs 32G 49M 32G 1% /run tmpfs tmpfs 32G 0 32G 0% /sys/fs/cgroup /dev/sda1 xfs 197M 139M 59M 71% /boot tmpfs tmpfs 6.3G 0 6.3G 0% /run/user/0 /dev/mapper/centos-home xfs 618G 73M 578G 1% /home ----------------------------------------Kind tips-------------------------------------------- If you want to reduce the partition space, you must first unmount the partition before reducing it. If there is a problem with uninstallation, the solution is as follows: [root@localhost ~]# umount /home/ umount: /home: device is busy. (In some cases useful information about processes that use the device is found by lsof(8) or fuser(1)) If it prompts that the uninstallation cannot be performed, it means that a process is occupying /home. Use the following command to terminate the occupying process: [root@localhost ~]# fuser -m -k /home /home: 1409 1519ce 1531e 1532e 1533e 1534e 1535e 1536e 1537e 1538e 1539e 1541e 1543e 1544e 1545e 1546e 1547e 1548e 1549e 1550e 1601m Unmounting the home partition again was successful. [root@localhost ~]# umount /home/ -k means automatically killing the process occupying the home partition! If you are not sure whether you want to kill all programs occupying the device, you can add a -i parameter, so that you will be asked before killing each program! (i.e. fuser -m -v -i -k /home) Summarize The above is the full content of this article. I hope that the content of this article will have certain reference learning value for your study or work. If you have any questions, you can leave a message to communicate. Thank you for your support for 123WORDPRESS.COM. You may also be interested in:
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