tech jogging As Linux systems have root file systems on a logical volume, it can be used Logical Volume Management (LVM) to resize the volume. The exercise of logical volume expanding is completed in case of adding an extra disk to a physical system or having a pool of storage in a virtual environment.
Run fdisk or gdisk partition tool. gdisk is used if the partition layout is GPT otherwise fdisk has to be used. gdisk will make your system unbootable if you don't have GPT partition. Both tools work identically when a new partiton is created.
How to figure out if GPT partition is present in your system? Assiming that sda is device with available space, run gdisk /dev/sda command.
This screen shows that your partition is GPT.
$ gdisk /dev/sda GPT fdisk (gdisk) version 0.8.10 Partition table scan: MBR: protective BSD: not present APM: not present GPT: present Found valid GPT with protective MBR; using GPT.
In case of MBR partition your screen is.
$ gdisk /dev/sda GPT fdisk (gdisk) version 0.8.10 Partition table scan: MBR: MBR only BSD: not present APM: not present GPT: not present *************************************************************** Found invalid GPT and valid MBR; converting MBR to GPT format in memory. THIS OPERATION IS POTENTIALLY DESTRUCTIVE! Exit by typing 'q' if you don't want to convert your MBR partitions to GPT format! ***************************************************************
Create a new logical volume partition. Enter 8E00 partition code.
Command (? for help): n Partition number (6-128, default 6): First sector (31457280-52428766, default = 31457280) or {+-}size{KMGTP}: Last sector (31457280-52428766, default = 52428766) or {+-}size{KMGTP}: Current type is 'Linux filesystem' Hex code or GUID (L to show codes, Enter = 8300): 8E00 Changed type of partition to 'Linux LVM'If you have received the message.
No free sectors available
You need to fix the pointer running commands.
a) Run expert mode.
Command (? for help): x
b) Fix the pointer.
Expert command (? for help): e Relocating backup data structures to the end of the disk
c) Return to main menu.
Expert command (? for help): m
d) Validate available space, for example.
Command (? for help): p Total free space is 52428800 sectors (25.0 GiB)
e) Rerun to create a new logical volume partition command. Enter 8E00 partition code.
Command (? for help): n Partition number (6-128, default 6): First sector (31457280-52428766, default = 31457280) or {+-}size{KMGTP}: Last sector (31457280-52428766, default = 52428766) or {+-}size{KMGTP}: Current type is 'Linux filesystem' Hex code or GUID (L to show codes, Enter = 8300): 8E00 Changed type of partition to 'Linux LVM'Validate your new partition
Command (? for help): p
The partion name must be
Linux LVM. If not, change the type running change a partition's type code.Command (? for help): t Partition number (1-3): 3 Hex code or GUID (L to show codes, Enter = 8300): 8E00
Apply changes.
Command (? for help): w Final checks complete. About to write GPT data. THIS WILL OVERWRITE EXISTING PARTITIONS!! Do you want to proceed? (Y/N): Y OK; writing new GUID partition table (GPT) to /dev/sda. Warning: The kernel is still using the old partition table. The new table will be used at the next reboot. The operation has completed successfully.
Notify the operation system about changes in the partition tables.
$ partprobe
Validate the new created partition. It can be used either fdisk or gdisk partition tool
$ fdisk -l /dev/sda WARNING: fdisk GPT support is currently new, and therefore in an experimental phase. Use at your own discretion. Disk /dev/sda: 26.8 GB, 26843545600 bytes, 52428800 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: gpt Disk identifier: 71DD2E79-BD1C-4713-9880-22664C87E57B # Start End Size Type Name 1 2048 2099199 1G Linux filesyste Linux filesystem 2 2099200 16777215 7G Linux LVM Linux LVM 3 16777216 20971519 2G Linux LVM Linux LVM 4 20971520 31457279 5G Linux LVM Linux LVM 5 34 2047 1007K BIOS boot BIOS boot partition 6 31457280 52428766 10G Linux LVM Linux LVM
Find out what logical groups/volumes are available.
$ lvs LV VG Attr LSize Pool Origin Data% Meta% Move Log Cpy%Sync Convert root centos -wi-ao---- <13.19g swap centos -wi-ao---- 820.00m
Our intertest is to add space to the root file system. The logical volume path is centos/root. In case of RHEL, it might be rhel/root.
Create a physical volume.
$ pvcreate /dev/sda6 WARNING: ext4 signature detected on /dev/sda6 at offset 1080. Wipe it? [y/n]: y Wiping ext4 signature on /dev/sda6. Physical volume "/dev/sda6" successfully created.
Extend centos volume group.
$ vgextend centos /dev/sda6 Volume group "centos" successfully extended
Figure out exact free space in PE. The field name is Free PE / Size and the value in the sample is 2559
$ vgdisplay --- Volume group --- VG Name centos System ID Format lvm2 Metadata Areas 4 Metadata Sequence No 8 VG Access read/write VG Status resizable MAX LV 0 Cur LV 2 Open LV 2 Max PV 0 Cur PV 4 Act PV 4 VG Size 23.98 GiB PE Size 4.00 MiB Total PE 6140 Alloc PE / Size 3581 / <13.99 GiB Free PE / Size 2559 / <10.00 GiB VG UUID ZPaYGz-7hbZ-2H6y-RS9W-x13x-2K81-pXCsA3
Extend centos/root logical volume
$ lvextend -l+2559 centos/root Size of logical volume centos/root changed from <13.19 GiB (3376 extents) to 23.18 GiB (5935 extents). Logical volume centos/root successfully resized.
XFS file system may be grown while mounted using the xfs_growfs command.
$ xfs_growfs /dev/centos/root meta-data=/dev/mapper/centos-root isize=512 agcount=9, agsize=406016 blks = sectsz=512 attr=2, projid32bit=1 = crc=1 finobt=0 spinodes=0 data = bsize=4096 blocks=3457024, imaxpct=25 = sunit=0 swidth=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 data blocks changed from 3457024 to 6077440
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