I can easily extend or shrink my logical volumes because I am using LVM in my virtual machines. Consider using LVM in production also because it gives you more flexibility then using normal hard drive partitions.
In this demo I'm using Oracle Linux 6.4.
Check disk free space after OS installation.
# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/vg_linuxtest-lv_root
4.9G 2.8G 2.0G 59% /
tmpfs 770M 100K 770M 1% /dev/shm
/dev/sda1 485M 55M 405M 12% /boot
Add "/u01" mount and assign some disk space for Oracle installation files.
Shutdown VM and add disk.
Partition new disk "/dev/sdb" using fdisk command.
# 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 0xa07249dd.
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: 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
Command action
e extended
p primary partition (1-4)
p
Partition number (1-4): 1
First cylinder (1-391, default 1):
Using default value 1
Last cylinder, +cylinders or +size{K,M,G} (1-391, default 391):
Using default value 391
Command (m for help): t
Selected partition 1
Hex code (type L to list codes): L
0 Empty 24 NEC DOS 81 Minix / old Lin bf Solaris
1 FAT12 39 Plan 9 82 Linux swap / So c1 DRDOS/sec (FAT-
2 XENIX root 3c PartitionMagic 83 Linux c4 DRDOS/sec (FAT-
3 XENIX usr 40 Venix 80286 84 OS/2 hidden C: c6 DRDOS/sec (FAT-
4 FAT16 <32M 41 PPC PReP Boot 85 Linux 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 FAT3 80 Old Minix be Solaris boot ff BBT
1e Hidden W95 FAT1
Hex code (type L to list codes): 8e
Changed system type of partition 1 to 8e (Linux LVM)
Command (m for help): w
The partition table has been altered!
Calling ioctl() to re-read partition table.
Syncing disks.
Notice that I have identified partition as "Linux LVM" choosing "8e" hex code.
Using pvcreate command create a physical volume for later use by the LVM.
# pvcreate /dev/sdb1 Physical volume "/dev/sdb1" successfully created
Create new volume group "vg_orabin". Later I can add or remove disks from this volume group.
# vgcreate vg_orabin /dev/sdb1 Volume group "vg_orabin" successfully created
Information about volume group.
# vgdisplay vg_orabin --- Volume group --- VG Name vg_orabin System ID Format lvm2 Metadata Areas 1 Metadata Sequence No 1 VG Access read/write VG Status resizable MAX LV 0 Cur LV 0 Open LV 0 Max PV 0 Cur PV 1 Act PV 1 VG Size 2.99 GiB PE Size 4.00 MiB Total PE 766 Alloc PE / Size 0 / 0 Free PE / Size 766 / 2.99 GiB VG UUID h3N1o5-AlYF-9nkL-PXiB-P8HK-tGAa-GlXPa5
Create logical volume using disk space from volume group.
# lvcreate --extents 766 -n lv_orabin vg_orabin Logical volume "lv_orabin" created
Create and mount filesystem.
# mkfs.ext4 /dev/mapper/vg_orabin-lv_orabin
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
196224< inodes, 784384 blocks
39219 blocks (5.00%) reserved for the super user
First data block=0
Maximum filesystem blocks=805306368
24 block groups
32768 blocks per group, 32768 fragments per group
8176 inodes per group
Superblock backups stored on blocks:
32768, 98304, 163840, 229376, 294912
Writing inode tables: done
Creating journal (16384 blocks): done
Writing superblocks and filesystem accounting information: done
This filesystem will be automatically checked every 25 mounts or
180 days, whichever comes first. Use tune2fs -c or -i to override.
# mkdir /u01
# mount /dev/mapper/vg_orabin-lv_orabin /u01
Check disk space available.
# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/vg_linuxtest-lv_root
4.9G 2.8G 2.0G 59% /
tmpfs 770M 88K 770M 1% /dev/shm
/dev/sda1 485M 55M 405M 12% /boot
/dev/mapper/vg_orabin-lv_orabin
3.0G 69M 2.8G 3% /u01
Hm, 2.8G is not enough free space for me. Let’s extend this mount adding another disk.
Shutdown VM and add disk.
Partition new disk and create physical volume for LVM.
# fdisk /dev/sdc
Device contains neither a valid DOS partition table, nor Sun, SGI or OSF disklabel
Building a new DOS disklabel with disk identifier 0x16953397.
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: 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
Command action
e extended
p primary partition (1-4)
p
Partition number (1-4): 1
First cylinder (1-652, default 1):
Using default value 1
Last cylinder, +cylinders or +size{K,M,G} (1-652, default 652):
Using default value 652
Command (m for help): t
Selected partition 1
Hex code (type L to list codes): 8e
Changed system type of partition 1 to 8e (Linux LVM)
Command (m for help): w
The partition table has been altered!
Calling ioctl() to re-read partition table.
Syncing disks.
# pvcreate /dev/sdc1
Physical volume "/dev/sdc1" successfully created
Check current status of volume group “vg_orabin”.
# vgdisplay vg_orabin --- Volume group --- VG Name vg_orabin System ID Format lvm2 Metadata Areas 1 Metadata Sequence No 2 VG Access read/write VG Status resizable MAX LV 0 Cur LV 1 Open LV 0 Max PV 0 Cur PV 1 Act PV 1 VG Size 2.99 GiB PE Size 4.00 MiB Total PE 766 Alloc PE / Size 766 / 2.99 GiB Free PE / Size 0 / 0 VG UUID h3N1o5-AlYF-9nkL-PXiB-P8HK-tGAa-GlXPa5
Extend volume group by adding physical volume "/dev/sdc1" using vgextend command.
# vgextend vg_orabin /dev/sdc1 Volume group "vg_orabin" successfully extended
Check volume group size - it is extended from 2.99G to 7.98G.
# vgdisplay vg_orabin --- Volume group --- VG Name vg_orabin System ID Format lvm2 Metadata Areas 2 Metadata Sequence No 3 VG Access read/write VG Status resizable MAX LV 0 Cur LV 1 Open LV 0 Max PV 0 Cur PV 2 Act PV 2 VG Size 7.98 GiB PE Size 4.00 MiB Total PE 2044 Alloc PE / Size 766 / 2.99 GiB Free PE / Size 1278 / 4.99 GiB VG UUID h3N1o5-AlYF-9nkL-PXiB-P8HK-tGAa-GlXPa5
Using pvscan command scan all disks and notice physical volumes with free space.
# pvscan PV /dev/sdb1 VG vg_orabin lvm2 [2.99 GiB / 0 free] PV /dev/sdc1 VG vg_orabin lvm2 [4.99 GiB / 4.99 GiB free] PV /dev/sda2 VG vg_linuxtest lvm2 [6.51 GiB / 0 free] Total: 3 [14.49 GiB] / in use: 3 [14.49 GiB] / in no VG: 0 [0 ]
With lvdisplay command display logical volume properties
Notice LV size = 2.99G.
# lvdisplay /dev/vg_orabin/lv_orabin --- Logical volume --- LV Path /dev/vg_orabin/lv_orabin LV Name lv_orabin VG Name vg_orabin LV UUID ypw9X1-vIsM-4rVF-NtVB-ACrf-f5nh-25p2sn LV Write Access read/write LV Creation host, time linuxtest.localdomain, 2014-10-23 13:19:56 +0200 LV Status available # open 0 LV Size 2.99 GiB Current LE 766 Segments 1 Allocation inherit Read ahead sectors auto - currently set to 256 Block device 252:2
I will add only 2G (of 5G) using lvextend command.
# lvextend -L +2G /dev/mapper/vg_orabin-lv_orabin /dev/sdc1 Extending logical volume lv_orabin to 4.99 GiB Logical volume lv_orabin successfully resized
Mount volume and check for free space.
# mount /dev/mapper/vg_orabin-lv_orabin /u01
# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/vg_linuxtest-lv_root
4.9G 2.8G 2.0G 59% /
tmpfs 770M 88K 770M 1% /dev/shm
/dev/sda1 485M 55M 405M 12% /boot
/dev/mapper/vg_orabin-lv_orabin
3.0G 69M 2.8G 3% /u01
Resize filesystem using resize2fs command:
# resize2fs /dev/mapper/vg_orabin-lv_orabin resize2fs 1.41.12 (17-May-2010) Filesystem at /dev/mapper/vg_orabin-lv_orabin is mounted on /u01; on-line resizing required old desc_blocks = 1, new_desc_blocks = 1 Performing an on-line resize of /dev/mapper/vg_orabin-lv_orabin to 1308672 (4k) blocks. The filesystem on /dev/mapper/vg_orabin-lv_orabin is now 1308672 blocks long.
Now I have 4.6G free space for "/u01" mount.
# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/vg_linuxtest-lv_root
4.9G 2.8G 2.0G 59% /
tmpfs 770M 88K 770M 1% /dev/shm
/dev/sda1 485M 55M 405M 12% /boot
/dev/mapper/vg_orabin-lv_orabin
5.0G 70M 4.6G 2% /u01
===========================================
Now I will try to extend root partition.
Newer Oracle Linux releases are using LVM by default during install.
Let’s see can I increase my root partition using commands above.
Display information about logical volumes using lvs command.
# lvs LV VG Attr LSize Pool Origin Data% Move Log Cpy%Sync Convert lv_root vg_linuxtest -wi-ao--- 4.97g lv_swap vg_linuxtest -wi-ao--- 1.54g lv_orabin vg_orabin -wi-a---- 4.99g
Check free space.
# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/vg_linuxtest-lv_root
4.9G 2.8G 2.0G 59% /
tmpfs 770M 88K 770M 1% /dev/shm
/dev/sda1 485M 55M 405M 12% /boot
Shutdown VM and add disk for extending root partition.
Partition new disk and create physical volume for LVM.
# fdisk /dev/sdd
Device contains neither a valid DOS partition table, nor Sun, SGI or OSF disklabel
Building a new DOS disklabel with disk identifier 0xf0608435.
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: 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
Command action
e extended
p primary partition (1-4)
p
Partition number (1-4): 1
First cylinder (1-652, default 1):
Using default value 1
Last cylinder, +cylinders or +size{K,M,G} (1-652, default 652):
Using default value 652
Command (m for help): t
Selected partition 1
Hex code (type L to list codes): 8e
Changed system type of partition 1 to 8e (Linux LVM)
Command (m for help): w
The partition table has been altered!
Calling ioctl() to re-read partition table.
Syncing disks.
# pvcreate /dev/sdd1
Physical volume "/dev/sdd1" successfully created
Check information about volume group.
# vgdisplay vg_linuxtest --- Volume group --- VG Name vg_linuxtest 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 6.51 GiB PE Size 4.00 MiB Total PE 1666 Alloc PE / Size 1666 / 6.51 GiB Free PE / Size 0 / 0 VG UUID TXkKYl-PIxu-s2xk-LsEB-sgTZ-TdcO-8wapCV
Extend volume group using new physical volume.
# vgextend vg_linuxtest /dev/sdd1 Volume group "vg_linuxtest" successfully extended
Logical volume status.
# lvdisplay /dev/vg_linuxtest/lv_root --- Logical volume --- LV Path /dev/vg_linuxtest/lv_root LV Name lv_root VG Name vg_linuxtest LV UUID VNgeT7-4yhd-XqRi-2da1-XTqT-qTvm-oVK2pz LV Write Access read/write LV Creation host, time linuxtest.localdomain, 2014-10-23 10:30:21 +0200 LV Status available # open 1 LV Size 4.97 GiB Current LE 1272 Segments 1 Allocation inherit Read ahead sectors auto - currently set to 256 Block device 252:0
Extend logical volume.
# lvextend /dev/mapper/vg_linuxtest-lv_root /dev/sdd1 Extending logical volume lv_root to 9.96 GiB Logical volume lv_root successfully resized
Resize filesystem.
# resize2fs /dev/mapper/vg_linuxtest-lv_root resize2fs 1.41.12 (17-May-2010) Filesystem at /dev/mapper/vg_linuxtest-lv_root is mounted on /; on-line resizing required old desc_blocks = 1, new_desc_blocks = 1 Performing an on-line resize of /dev/mapper/vg_linuxtest-lv_root to 2611200 (4k) blocks. The filesystem on /dev/mapper/vg_linuxtest-lv_root is now 2611200 blocks long.
Check disk free space. Notice that I have 6.6G of free space for my root partition.
# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/vg_linuxtest-lv_root
9.9G 2.8G 6.6G 30% /
tmpfs 770M 88K 770M 1% /dev/shm
/dev/sda1 485M 55M 405M 12% /boot
WARNING! Be very careful when using commands from blog post on your production system. These are dangerous commands which can cause loss of data or many other problems. I’ve used this commands in my test environment for educational purpose and it is possible that I have made mistakes in this demo. After all I am only simple Oracle DBA not Linux SA :-)
REFERENCES
http://www.linuxuser.co.uk/features/resize-your-disks-on-the-fly-with-lvm
http://www.rootusers.com/how-to-increase-the-size-of-a-linux-lvm-by-adding-a-new-disk/
https://wiki.archlinux.org/index.php/LVM
Thank you Marco, for a thorough and nice post.
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