Extended root partitions: Introduction to the usage of each partition and introduction to extended root partitions

Extended root partitions: Introduction to the usage of each partition and introduction to extended root partitions

List the usage of each partition:

# Df-ThFilesystem Type Size Used Avail Use % Mounted on/dev/mapper/centos-root xfs 997 M 994 M 2.9 M 100%/devtmpfs 915 M 0 915 M 0%/devtmpfs tmpfs 921 M 0 921 M 0%/dev/shmtmpfs tmpfs 921 M 17 M 905 M 2%/runtmpfs tmpfs 921 M 0 921 M 0%/sys/fs/cgroup/dev/mapper/centos- usr xfs 4.9G 1.6G 3.4G 33%/usr/dev/sda1 xfs 97 M 66 M 31 M 69%/boot/dev/mapper/centos-var xfs 2.4G 473 M 1.9G 21%/var:/dev/mapper /Centos-root has used 100%. We are going to resize it. Add a new virtual disk to VirtualBox: Disable the operating system first. Select the current VM in VirtualBox, set-> storage-> controller-> SATA controller, and click the icon "add virtual hard disk" to create a new virtual hard disk. I added a virtual disk of 3GiB size, saved it, and started the virtual machine again. To create a new partition, first check the existing Disk: # fdisk-l result: Disk/dev/sda: 21.5 GB, 21474836480 bytes, 41943040 sectorsUnits = sectors of 1*512 = 512 bytesSector size (logical/physical): 512 bytes/512 bytesI/O size (minimum/optimal): 512 bytes/512 bytesDisk label type: dosDisk identifier: 0x000940ec Device Boot Start End Blocks Id System/dev/sda1 * 2048 206847 102400 83 Linux/dev/sda2 206848 41943039 20868096 8e Linux LVMD Isk/dev/sdb: 3221 MB, 3221225472 bytes, 6291456 sectorsUnits = sectors of 1*512 = 512 bytesSector size (logical/physical ): 512 bytes/512 bytesI/O size (minimum/optimal): 512 bytes/512 bytesDisk/dev/mapper/centos-swap: 2097 MB, 2097152000 bytes, 4096000 sectorsUnits = sectors of 1*512 = 512 bytesSector size (logical/physical): 512 bytes/512 bytesI/O size (minimum/optimal): 512 bytes/5 12 bytesDisk/dev/mapper/centos-usr: 5242 MB, 5242880000 bytes, 10240000 sectorsUnits = sectors of 1*512 = 512 bytesSector size (logical/physical ): 512 bytes/512 bytesI/O size (minimum/optimal): 512 bytes/512 bytesDisk/dev/mapper/centos-root: 1048 MB, 1048576000 bytes, 2048000 sectorsUnits = sectors of 1*512 = 512 bytesSector size (logical/physical): 512 bytes/512 bytesI/O size (minimum /Optimal): 512 bytes/512 bytes... you can see the new disk/dev/sdb. Partition the new disk: # fdisk/dev/sdb in the interactive mode of fdisk, and enter: n -- create new partition p -- create primary partition <press enter> -- default Partition Number <press enter> -- default start sector position. <Press enter> -- default end sector position. W -- write the partition table to split the entire disk into one partition. Let's take a look at the current disk situation: # fdisk-l has a new partition: device Boot Start End Blocks Id System/dev/sdb1 2048 6291455 3144704 83 Linux uses the new partition for extension/root to view the next volume group first: # vgdisplay-vFinding all volume groups Finding volume group "centos" --- 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 5 Open LV 5 Max PV 0 Cur PV 1 Act PV 1 VG Siz E 19.90 GiB PE Size 4.00 MiB Total PE 5094 Alloc PE/Size 5093/19 .89 GiB Free PE/Size 1/4.00 MiB vg uuid vtJL08-7Jxi-5IqK-3fUg-Pben-682a-wiv2GL --- Logical volume --- LV Path/dev/centos/root LV Name root VG Name centos lv uuid ZWTgoT-AMWs-g54v-dZA1-NQUj-mqGa-8tmr4U LV Write Access read/write LV Creation host, time localhost, 21:59:31-0400 LV Status available # open 1 LV Size 10 00.00 MiB Current LE 250 Segments 1 Allocation inherit Read ahead sectors auto currently set to 256 Block device 253: 2 ......... --- Physical volumes --- PV Name/dev/sda2 pv uuid fiVH1e-lwfi-63Lr-oIlK-GDZI-dcuZ-T04VlC PV Status allocatable Total PE/Free PE 5094/1 You can see the current volume group Name "centos ". Create a physical volume for the newly added partition: # pvcreate/dev/sdb1 indicates whether to erase the xfs signature. I selected y: WARNING: xfs signature detected on/dev/sdb1 at offset 0. wipe it? [Y/n] y Wiping xfs signature on/dev/sdb1. Physical volume "/dev/sdb1" successfully created view result: # pvdisplay displays the newly created Physical volume of 3GiB size: --- Physical volume --- PV Name/dev/sda2 VG Name centos PV Size 19.90 GiB/not usable 3.00 MiB Allocatable yes PE Size 4.00 MiB Total PE 5094 Free PE 1 Allocated PE 5093 pv uuid fiVH1e-lwfi-63Lr-oIlK-GDZI-dcuZ-T04VlC "/dev/sdb1" is a new physical volume of "3.00 GiB "--- NEW Physical volume --- PV Name/dev/sdb1 VG Name PV Size 3.00 GiB Allocatable no pe Size 0 Total PE 0 Free PE 0 Allocated PE 0 pv uuid VGXSAn-UiZ0-Fy40-eQxb-53xA-5hZM-3eGPg0 expansion volume group, "centos" is the volume group name found by the vgdisplay command: # vgextend centos/dev/sdb1 indicates that the extension is successful. Check the logical volume below: # lvdisplay shows that the current LV Size of/dev/centos/root is 1000MiB. The following extended logical volume/dev/centos/root: # lvextend-L + 3G/dev/centos/root note: + 3G is the size of our new partition. After expansion, perform the following steps: # xfs_growfs/dev/centos/root to expand the file system. Complete. Because the xfs partition used to install CentOS is used, the xfs_growfs command is used to expand the file system size. Otherwise, use the resize2fs command. View the result: # df-Th/root has been expanded to 4GiB: filesystem Type Size Used Avail Use % Mounted on/dev/mapper/centos-root xfs 4.0G 995 M 3.1G 25%/devtmpfs 915 M 0 915 M 0%/devtmpfs tmpfs 921 M 0 921 M 0%/dev/shmtmpfs tmpfs 921 M 8.4 M 913 M 1%/runtmpfs tmpfs 921 M 0 921 M 0%/sys/fs/cgroup/dev/mapper/centos-usr xfs 4.9G 1.6G 3.4G 33%/usr/dev/mapper/centos-home xfs 9.8G 391 M 9.4G 4%/home/dev/mapper/centos-var xfs 2.4G 469 M 1.9G 20%/var/dev/sda1 xfs 97 M 66 M 31 M 69%/boot