{"id":10844,"date":"2024-12-14T08:15:41","date_gmt":"2024-12-14T08:15:41","guid":{"rendered":"https:\/\/blog.trustedhosting.in\/?p=10844"},"modified":"2024-12-14T08:15:41","modified_gmt":"2024-12-14T08:15:41","slug":"extending-an-lvm-disk-partition-in-linux","status":"publish","type":"post","link":"https:\/\/www.webystrata.com\/blog\/extending-an-lvm-disk-partition-in-linux\/","title":{"rendered":"Extending an LVM disk partition in Linux"},"content":{"rendered":"

\"Extending<\/a><\/h1>\n

Extending an LVM disk partition in Linux<\/h1>\n
When you purchase additional disk space – either in the form of additional hard disks, or an eCloud disk extension – there are some steps that need to be performed in order to make the additional disk space available.<\/p>\n

There are two ways that the automation might present additional space to you. The default for Linux servers is to add a new virtual disk to your server<\/a>, and then extend the LVM for your chosen partition with the new disk.<\/p>\n

On Windows servers<\/a>, the default is to change the size of the underlying virtual disk, which can sometimes be applied to Linux servers<\/a> under certain conditions.<\/p>\n

\n

Please be aware that this article uses specific examples, such as\u00a0sdb<\/em>\u00a0or\u00a0\/dev\/mapper\/eCloud-root<\/em>.<\/p>\n

You may have different requirements or configurations in terms of device names and volumes.<\/p>\n

Performing this incorrectly may make irreversible changes to your filesystem or cause data loss, so please proceed with care and caution.<\/p>\n

Once an extension has been started, it cannot be reverted.<\/p><\/blockquote>\n<\/div>\n

\n

Identify the type of extension that was performed<\/h2>\n

As such, we must first identify which form of disk expansion has been applied to your virtual machine (VM).<\/p>\n

Firstly we need to rescan the SCSI hosts:<\/p>\n

\n
\n
[<\/span>root@ssh ~]<\/span># for i in \/sys\/class\/scsi_host\/host*\/scan; do echo \"- - -\" > $i; done<\/span>\r\n[<\/span>root@ssh ~]<\/span># for i in \/sys\/class\/scsi_device\/*\/device\/rescan; do echo \"1\" > $i; done<\/span>\r\n<\/pre>\n<\/div>\n<\/div>\n
Next, grab a list of the current physical volumes configured in LVM:<\/p>\n
\n
\n
[<\/span>root@ssh ~]<\/span># pvs<\/span>\r\n  PV         VG     Fmt  Attr PSize  PFree\r\n  \/dev\/sda2  eCloud lvm2 a--   9<\/span>.51g    0<\/span>\r\n  \/dev\/sdb   eCloud lvm2 a--  10<\/span>.00g    0<\/span>\r\n[<\/span>root@ssh ~]<\/span>#<\/span>\r\n<\/pre>\n<\/div>\n<\/div>\n
\n
Note that\u00a0\/dev\/sda1<\/strong>\u00a0is not supposed part of this list, as this contains your information for\u00a0\/boot<\/strong>.<\/p><\/blockquote>\n<\/div>\n
Then, check whether there are any new disks of the requested additional size that have been created; or whether one of the disks has changed size:<\/p>\n
\n
Example of resized disk<\/h3>\n
Here you can see that the\u00a0\/dev\/sdb<\/span><\/code>\u00a0device is showing as 26.1G, while the output from\u00a0pvs<\/span><\/code>\u00a0for\u00a0\/dev\/sdb<\/span><\/code>\u00a0is only 10G.<\/p>\n
\n
\n
[<\/span>root@ssh ~]<\/span># fdisk -l<\/span>\r\n\r\nDisk \/dev\/sda: 21<\/span>.5 GB, 21474836480<\/span> bytes, 41943040<\/span> sectors\r\nUnits<\/span> =<\/span> sectors of 1<\/span> * 512<\/span> =<\/span> 512<\/span> bytes\r\nSector size (<\/span>logical\/physical)<\/span>: 512<\/span> bytes \/ 512<\/span> bytes\r\nI\/O size (<\/span>minimum\/optimal)<\/span>: 512<\/span> bytes \/ 512<\/span> bytes\r\nDisk label type: dos\r\nDisk identifier: 0x00001caf\r\n\r\n   Device Boot      Start         End      Blocks   Id  System\r\n\/dev\/sda1   *        2048<\/span>     1026047<\/span>      512000<\/span>   83<\/span>  Linux\r\n\/dev\/sda2         1026048<\/span>    20971519<\/span>     9972736<\/span>   8e  Linux LVM\r\n\r\nDisk \/dev\/mapper\/eCloud-root: 19<\/span>.9 GB, 19893583872<\/span> bytes, 38854656<\/span> sectors\r\nUnits<\/span> =<\/span> sectors of 1<\/span> * 512<\/span> =<\/span> 512<\/span> bytes\r\nSector size (<\/span>logical\/physical)<\/span>: 512<\/span> bytes \/ 512<\/span> bytes\r\nI\/O size (<\/span>minimum\/optimal)<\/span>: 512<\/span> bytes \/ 512<\/span> bytes\r\n\r\n\r\nDisk \/dev\/mapper\/eCloud-swap: 1048<\/span> MB, 1048576000<\/span> bytes, 2048000<\/span> sectors\r\nUnits<\/span> =<\/span> sectors of 1<\/span> * 512<\/span> =<\/span> 512<\/span> bytes\r\nSector size (<\/span>logical\/physical)<\/span>: 512<\/span> bytes \/ 512<\/span> bytes\r\nI\/O size (<\/span>minimum\/optimal)<\/span>: 512<\/span> bytes \/ 512<\/span> bytes\r\n\r\n\r\nDisk \/dev\/sdb: 16<\/span>.1 GB, 16106127360<\/span> bytes, 31457280<\/span> sectors\r\nUnits<\/span> =<\/span> sectors of 1<\/span> * 512<\/span> =<\/span> 512<\/span> bytes\r\nSector size (<\/span>logical\/physical)<\/span>: 512<\/span> bytes \/ 512<\/span> bytes\r\nI\/O size (<\/span>minimum\/optimal)<\/span>: 512<\/span> bytes \/ 512<\/span> bytes\r\n\r\n[<\/span>root@ssh ~]<\/span>#<\/span>\r\n<\/pre>\n<\/div>\n<\/div>\n
In this case, proceed with the\u00a0resized disk method.<\/strong><\/p>\n<\/section>\n
\n
\n
Example of additional disk<\/h3>\n
If you can\u2019t see a resized disk, a new disk has probably been added.<\/p>\n
Check the output of\u00a0dmesg<\/span><\/code>\u00a0for information about a new disk being added:<\/p>\n
\n
\n
[<\/span>root@ssh ~]<\/span># dmesg<\/span>\r\n[<\/span>13955<\/span>.155726]<\/span> scsi 2<\/span>:0:2:0: Direct-Access     VMware   Virtual disk     1<\/span>.0  PQ: 0<\/span> ANSI: 2<\/span>\r\n[<\/span>13955<\/span>.157712]<\/span> sd 2<\/span>:0:2:0: Attached scsi generic sg3 type<\/span> 0<\/span>\r\n[<\/span>13955<\/span>.159156]<\/span> sd 2<\/span>:0:2:0: [<\/span>sdc]<\/span> 10485760<\/span> 512<\/span>-byte logical blocks: (<\/span>5<\/span>.36 GB\/5.00 GiB)<\/span>\r\n[<\/span>13955<\/span>.159210]<\/span> sd 2<\/span>:0:2:0: [<\/span>sdc]<\/span> Write Protect is off\r\n[<\/span>13955<\/span>.159214]<\/span> sd 2<\/span>:0:2:0: [<\/span>sdc]<\/span> Mode Sense: 61<\/span> 00<\/span> 00<\/span> 00<\/span>\r\n[<\/span>13955<\/span>.159293]<\/span> sd 2<\/span>:0:2:0: [<\/span>sdc]<\/span> Cache data unavailable\r\n[<\/span>13955<\/span>.159296]<\/span> sd 2<\/span>:0:2:0: [<\/span>sdc]<\/span> Assuming drive cache: write through\r\n[<\/span>13955<\/span>.161472]<\/span>  sdc: unknown partition table\r\n[<\/span>13955<\/span>.161769]<\/span> sd 2<\/span>:0:2:0: [<\/span>sdc]<\/span> Attached SCSI disk\r\n<\/pre>\n<\/div>\n<\/div>\n
Then confirm that the disk that was added matches the size of the disk that you\u2019ve purchased (sdc<\/span><\/code>\u00a0in this case):<\/p>\n
\n
\n
root@ssh ~]<\/span># fdisk -l \/dev\/sdc<\/span>\r\n\r\nDisk \/dev\/sdc: 5368<\/span> MB, 5368709120<\/span> bytes, 10485760<\/span> sectors\r\nUnits<\/span> =<\/span> sectors of 1<\/span> * 512<\/span> =<\/span> 512<\/span> bytes\r\nSector size (<\/span>logical\/physical)<\/span>: 512<\/span> bytes \/ 512<\/span> bytes\r\nI\/O size (<\/span>minimum\/optimal)<\/span>: 512<\/span> bytes \/ 512<\/span> bytes\r\n\r\n[<\/span>root@ssh ~]<\/span>#<\/span>\r\n<\/pre>\n<\/div>\n<\/div>\n
I added 5G to the VM, and this disk is ~5G in size, so we\u2019ve identified where it was added.<\/p>\n
Now proceed with the\u00a0additional disk method.<\/strong><\/p>\n<\/section>\n<\/section>\n<\/section>\n
\n
\n
Resized disk method<\/h1>\n
We\u2019ve identified that one of the disks has been resized –\u00a0sdb<\/span><\/code>\u00a0in this case.<\/p>\n
\n
Expand the partition if necessary<\/h2>\n
If the LVM PV refers to a partition on a disk (e.g.\u00a0\/dev\/sdb3<\/span><\/code>) rather than a complete disk (\/dev\/sdb<\/span><\/code>), you\u2019ll first need to expand the partition to use the new space. Use the\u00a0growpart<\/span><\/code>\u00a0command to do this:<\/p>\n
growpart<\/span>\u00a0<disk><\/span>\u00a0<partition<\/span>\u00a0number><\/span><\/code><\/p>\n
for example<\/p>\n
growpart<\/span>\u00a0\/dev\/sdb<\/span>\u00a03<\/span><\/code><\/p>\n
Note that it is intentional that there is a space between the\u00a0\/dev\/sdb<\/span><\/code>\u00a0and\u00a03<\/span><\/code>. It\u2019s also important to note that this will only work if the partition number is the highest numbered on on the disk. For example, if you had\u00a0\/dev\/sdb1<\/span><\/code>,\u00a0\/dev\/sdb2<\/span><\/code>,\u00a0\/dev\/sdb3<\/span><\/code>,\u00a0\/dev\/sdb4<\/span><\/code>, and your PV was\u00a0\/dev\/sdb3<\/span><\/code>, you couldn\u2019t expand\u00a0\/dev\/sdb3<\/span><\/code>\u00a0because\u00a0\/dev\/sdb4<\/span><\/code>\u00a0would be in the way. Contact support for advice if you find yourself in this situation.<\/p>\n
The\u00a0growpart<\/span><\/code>\u00a0command isn\u2019t always installed by default on a server, you may need to install it first using\u00a0yum<\/span><\/code>\u00a0\/\u00a0apt<\/span><\/code>\u00a0\/\u00a0dnf<\/span><\/code>\u00a0as appropriate.<\/p>\n<\/section>\n
\n
Resize the physical volume to use the new space<\/h2>\n
While the operating system (OS) can see the additional space, we\u2019ve still got to make this usable.<\/p>\n
First, you\u2019ll need to get LVM to recognise that the PV has changed size:<\/p>\n
\n
\n
[<\/span>root@ssh ~]<\/span># pvresize \/dev\/sdb<\/span>\r\n  Physical volume \"\/dev\/sdb\"<\/span> changed\r\n  1<\/span> physical volume(<\/span>s)<\/span> resized \/ 0<\/span> physical volume(<\/span>s)<\/span> not resized\r\n[<\/span>root@ssh ~]<\/span>#<\/span>\r\n<\/pre>\n<\/div>\n<\/div>\n
\n
Continue reading from the\u00a0final steps\u00a0section to complete the process.<\/strong><\/p>\n<\/section>\n<\/section>\n
\n
\n
Additional disk method<\/h1>\n
We\u2019ve identified that a new disk was added –\u00a0sdc<\/span><\/code>\u00a0in this case.<\/p>\n
\n
Create a physical volume from the new device<\/h2>\n
We need to create a new physical volume for the new device (sdc<\/span><\/code>) so that we can use it in LVM:<\/p>\n
\n
\n
[<\/span>root@ssh ~]<\/span># pvcreate \/dev\/sdc<\/span>\r\n  Physical volume \"\/dev\/sdc\"<\/span> successfully created\r\n[<\/span>root@ssh ~]<\/span>#<\/span>\r\n<\/pre>\n<\/div>\n<\/div>\n
Then confirm that it shows up in\u00a0pvs<\/span><\/code>:<\/p>\n
\n
\n
[<\/span>root@ssh ~]<\/span># pvs<\/span>\r\n  PV         VG     Fmt  Attr PSize  PFree\r\n  \/dev\/sda2  eCloud lvm2 a--   9<\/span>.51g    0<\/span>\r\n  \/dev\/sdb   eCloud lvm2 a--  15<\/span>.00g    0<\/span>\r\n  \/dev\/sdc          lvm2 ---   5<\/span>.00g 5<\/span>.00g\r\n[<\/span>root@ssh ~]<\/span>#<\/span>\r\n<\/pre>\n<\/div>\n<\/div>\n<\/section>\n
\n
Add the new physical volume into the volume group<\/h2>\n
So that we can assign the new disk space to the logical volume, we need to first add the physical volume into the volume group:<\/p>\n
\n
\n
[<\/span>root@ssh ~]<\/span># vgextend eCloud \/dev\/sdc<\/span>\r\n  Volume group \"eCloud\"<\/span> successfully extended\r\n[<\/span>root@ssh ~]<\/span>#<\/span>\r\n<\/pre>\n<\/div>\n<\/div>\n
Then confirm that the VG shows the right total size:<\/p>\n
\n
\n
[<\/span>root@ssh ~]<\/span># vgs<\/span>\r\n  VG     #PV #LV #SN Attr   VSize  VFree<\/span>\r\n  eCloud   3<\/span>   2<\/span>   0<\/span> wz--n- 29<\/span>.50g 5<\/span>.00g\r\n[<\/span>root@ssh ~]<\/span>#<\/span>\r\n<\/pre>\n<\/div>\n<\/div>\n
\n
Continue reading from the\u00a0final steps\u00a0section to complete the process.<\/strong><\/p>\n<\/section>\n<\/section>\n
\n
\n
Final steps<\/h1>\n
Both methods of adding disk space to an eCloud VM are the same towards the end, so you can continue from here.<\/p>\n
We need to grow the LV over the new free space – for most people this will be the\u00a0\/<\/span><\/code>\u00a0partition, but if you have more than one partition, take care to ensure you\u2019re resizing the right one:<\/p>\n
\n
\n
[<\/span>root@ssh ~]<\/span># lvs<\/span>\r\n  LV   VG     Attr       LSize    Pool Origin Data%  Meta%  Move Log Cpy%Sync Convert\r\n  root eCloud -wi-ao----   18<\/span>.53g\r\n  swap eCloud -wi-ao---- 1000<\/span>.00m\r\n[<\/span>root@ssh ~]<\/span>#<\/span>\r\n<\/pre>\n<\/div>\n<\/div>\n
In this case, we\u2019ll be doing the most common extension of\u00a0\/<\/span><\/code>. Note the path in this command is\u00a0\/dev\/mapper\/VG\/LV<\/span><\/code>\u00a0from the table above:<\/p>\n
\n
\n
[<\/span>root@ssh ~]<\/span># lvresize -l +100%FREE \/dev\/mapper\/eCloud\/root<\/span>\r\n  Size of logical volume eCloud\/root changed from 18<\/span>.53 GiB (<\/span>4743<\/span> extents)<\/span> to 23<\/span>.53 GiB (<\/span>6023<\/span> extents)<\/span>.\r\n  Logical volume root successfully resized.\r\n[<\/span>root@ssh ~]<\/span>#<\/span>\r\n<\/pre>\n<\/div>\n<\/div>\n
Confirm that this has resized the LV as expected:<\/p>\n
\n
\n
root@ssh ~]<\/span># lvs<\/span>\r\n  LV   VG     Attr       LSize    Pool Origin Data%  Meta%  Move Log Cpy%Sync Convert\r\n  root eCloud -wi-ao----   23<\/span>.53g\r\n  swap eCloud -wi-ao---- 1000<\/span>.00m\r\n[<\/span>root@ssh ~]<\/span>#<\/span>\r\n<\/pre>\n<\/div>\n<\/div>\n
\n
Resize the filesystem to make the new space available<\/h2>\n
Now that the disk and LV show the correct sizes, we can go ahead and resize the filesystem. Some servers use the\u00a0ext<\/span><\/code>\u00a0filesystem type, and others user\u00a0xfs<\/span><\/code>\u00a0– to identify which yours uses, run the following:<\/p>\n
\n
\n
[<\/span>root@ssh ~]<\/span># df -T<\/span>\r\nFilesystem              Type     1K-blocks    Used Available Use% Mounted on\r\n\/dev\/mapper\/eCloud-root xfs       19417088<\/span> 2235516<\/span>  17181572<\/span>  12<\/span>% \/\r\ndevtmpfs                devtmpfs   1929244<\/span>       0<\/span>   1929244<\/span>   0<\/span>% \/dev\r\ntmpfs                   tmpfs      1939460<\/span>       0<\/span>   1939460<\/span>   0<\/span>% \/dev\/shm\r\ntmpfs                   tmpfs      1939460<\/span>    8656<\/span>   1930804<\/span>   1<\/span>% \/run\r\ntmpfs                   tmpfs      1939460<\/span>       0<\/span>   1939460<\/span>   0<\/span>% \/sys\/fs\/cgroup\r\n\/dev\/sda1               xfs         508588<\/span>  211732<\/span>    296856<\/span>  42<\/span>% \/boot\r\ntmpfs                   tmpfs       387892<\/span>       0<\/span>    387892<\/span>   0<\/span>% \/run\/user\/0\r\n[<\/span>root@ssh ~]<\/span>#<\/span>\r\n<\/pre>\n<\/div>\n<\/div>\n
In this example, the server is using\u00a0xfs<\/span><\/code>.<\/p>\n
\n
Resizing XFS filesystems<\/h3>\n
To resize an\u00a0xfs<\/span><\/code>\u00a0filesystem, run the following – noting the format of\u00a0\/dev\/mapper\/VG-LV<\/span><\/code>\u00a0on the device name:<\/p>\n
\n
\n
[<\/span>root@ssh ~]<\/span># xfs_growfs \/dev\/mapper\/eCloud-root<\/span>\r\n<\/pre>\n<\/div>\n<\/div>\n
Then confirm that the disk shows the correct size in\u00a0df<\/span>\u00a0-h<\/span><\/code>.<\/p>\n<\/section>\n
\n
Resizing EXT filesystems<\/h3>\n
To resize an\u00a0ext<\/span><\/code>\u00a0filesystem, run the following – noting the format of\u00a0\/dev\/mapper\/VG-LV<\/span><\/code>\u00a0on the device name:<\/p>\n
\n
\n
[<\/span>root@ssh ~]<\/span># resize2fs \/dev\/mapper\/eCloud-root<\/span>\r\n<\/pre>\n<\/div>\n<\/div>\n
Then confirm that the disk shows the correct size in\u00a0df<\/span>\u00a0-h<\/span><\/code>.<\/p>\n<\/section>\n<\/section>\n<\/section>\n","protected":false},"excerpt":{"rendered":"
Extending an LVM disk partition in Linux When you purchase additional disk space – either in the form of additional…<\/p>\n","protected":false},"author":1,"featured_media":10845,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[9],"tags":[],"class_list":["post-10844","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-linux"],"_links":{"self":[{"href":"https:\/\/www.webystrata.com\/blog\/wp-json\/wp\/v2\/posts\/10844","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.webystrata.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.webystrata.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.webystrata.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.webystrata.com\/blog\/wp-json\/wp\/v2\/comments?post=10844"}],"version-history":[{"count":1,"href":"https:\/\/www.webystrata.com\/blog\/wp-json\/wp\/v2\/posts\/10844\/revisions"}],"predecessor-version":[{"id":10846,"href":"https:\/\/www.webystrata.com\/blog\/wp-json\/wp\/v2\/posts\/10844\/revisions\/10846"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.webystrata.com\/blog\/wp-json\/wp\/v2\/media\/10845"}],"wp:attachment":[{"href":"https:\/\/www.webystrata.com\/blog\/wp-json\/wp\/v2\/media?parent=10844"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.webystrata.com\/blog\/wp-json\/wp\/v2\/categories?post=10844"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.webystrata.com\/blog\/wp-json\/wp\/v2\/tags?post=10844"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}