Introduction

Thinly Provisioned Logical volume: In our previous LVM guides we have completed with setting up a linear and stripped LVM. Further, Let’s start to explore more on LVM with thin provisioning.

Those who are not aware of the difference between Thick and Thin may have bit difficultly to understand this guide. To explain it in plain English,

Thick means it will occupy the whole space once we allocate something. Example a fat guy sitting on a couch and he fit it. No space left on couch.

But, The thin provision will be opposite to thick, Once we allocate something it won’t allocate the whole space, according to the growth it will occupy the allocated space in future. Example slim guy sitting on a couch and still couch have enough space to allocate something.

How Thinly Provisioned Volumes works

Now, let explain how thinly provisioned logical volume will work. For instance, your total size of the storage is 500 MB. But a guy from application team may request for 250 MB which is 50% of total storage size.

Whenever a request comes from Application team it will be huge in size. For example, it can be 250 MB or 500 MB. But the actual size they might not use more than 50% of provisioned space. In this place, they may argue to provide the actual requested size. In such a scenario, we can use thinly provisioned disks. Because thinly provisioned disk will visible as whole disk space (250 MB) to end-user and it won’t occupy the total size once we provision. Instead, it will grow till allocated size (250 MB) when the files are written to it. That means if they have application data around 25 MB then the actually occupied disk will be 25 MB thus the thin provisioned disk works.

Explanation with Scenario

You have four users and each one needs 100 MB of the disk for their data’s.

If we allocate this requirement from a thin pool then it will allocate virtually 100 MB for each User. But behind the scene, it will consume only the size of data’s writing to it. It means, User 1 may write only 50 MB of data, User 2 will write 75 MB of data thus remaining users user 3 and 4 may write not more than 100 MB of data so the total will be 225 MB of data.

But the actual disk size for each user is 100 MB and the total size of the storage is 500 MB so 100 MB x 4 Users = 400 MB. From this, we can assume that we are on a safe side because the user’s current usage is below the allocated size of 100 MB and the thin pool still have enough space to create more thin volumes.

What is Over Provisioning

Now, Maybe two more users need 100 MB each, but already allocated size crossed 400 MB. While we provision more 200 MB it will become a total of 600 MB. Providing more than what we have is called Over Provisioning.

In Simple words

Simply the concept of the thin provision is the possibility of provisioning more than the actual available size. It means out of total 500 MB you can create even 1 GB file system for a user and there will be no risk until unless the user not going to fill up the disk by vigorously writing to it.

Steps for creating thin volumes are as follows.

  1. Check for space in Volume Group.
  2. Create a thin pool
  3. Creating thin volumes from the thin pool.
  4. manipulate file system on thin volumes.
  5. Create the mount points to mount the filesystem.
  6. Verify the thin Pool and thin volume size.

Let’s start creating a thin pool and thin volumes as per the above explanation.

Creating a Thin Pool

To create a thin pool we need to have a basic Volume group.

[root@fileserver ~]# vgs
   VG      #PV #LV #SN Attr   VSize    VFree   
   centos    1   3   0 wz--n-  <99.00g    4.00m
   vg_thin   1   0   0 wz--n- 1020.00m 1020.00m
[root@fileserver ~]#

While listing we have two volume groups, centos vg already used for OS. Volume group vg_thin will be used throughout our guide.

Then create a thin pool on top of the existing Volume group.

# lvcreate -L 500M --thinpool tp_pool vg_thin

We have created only 500 MB of thin pool remaining 500 MB left free under our VG for future use.

[root@fileserver ~]# lvcreate -L 500M --thinpool tp_pool vg_thin
   Thin pool volume with chunk size 64.00 KiB can address at most 15.81 TiB of data.
   Logical volume "tp_pool" created.
[root@fileserver ~]#

Once created list the thin pool with lvs command.

# lvs

Here we need to understand a few of things from the output of lvs.

Listing the thin pool in Thinly Provisioned Logical volume
Listing the thin pool
  1. The leading “t” means it’s a thin pool.
  2. Size of the thin pool.
  3. Current data usage of the thin pool.
  4. Metadata usage under this thin pool.

Creating Thin Volumes

Once a thin pool created then we can go ahead with creating the thin volumes from the available space. In our setup, Initially, we are creating with four numbers of thin volumes each one with 100 MB of size.

# lvcreate -V 100M --thin -n tp_lv_user1 vg_thin/tp_pool
# lvcreate -V 100M --thin -n tp_lv_user2 vg_thin/tp_pool
# lvcreate -V 100M --thin -n tp_lv_user3 vg_thin/tp_pool
# lvcreate -V 100M --thin -n tp_lv_user4 vg_thin/tp_pool

Output for reference

[root@fileserver ~]# lvcreate -V 100M --thin -n tp_lv_user1 vg_thin/tp_pool
   Logical volume "tp_lv_user1" created.
 [root@fileserver ~]# lvcreate -V 100M --thin -n tp_lv_user2 vg_thin/tp_pool
   Logical volume "tp_lv_user2" created.
 [root@fileserver ~]# lvcreate -V 100M --thin -n tp_lv_user3 vg_thin/tp_pool
   Logical volume "tp_lv_user3" created.
 [root@fileserver ~]# lvcreate -V 100M --thin -n tp_lv_user4 vg_thin/tp_pool
   Logical volume "tp_lv_user4" created.
[root@fileserver ~]#

To get more detailed information about the thin pool and thin volumes we can run lvdisplay on the related Volume Group. The output will be a bit long with more detailed informations.

If you have noticed Allocated pool data and Mapped Size from below output it will be 0.00% because none of the data yet copied under this thin pool or volumes. The same thing we can notice for all thin volumes as well.

[root@fileserver ~]# lvdisplay vg_thin
   --- Logical volume ---
   LV Name                tp_pool
   VG Name                vg_thin
   LV UUID                mQL6BA-8kfl-LzLw-7npA-F5Zg-ntHw-qfNilc
   LV Write Access        read/write
   LV Creation host, time fileserver, 2019-08-30 03:52:49 +0300
   LV Pool metadata       tp_pool_tmeta
   LV Pool data           tp_pool_tdata
   LV Status              available
   # open                 5
   LV Size                500.00 MiB
   Allocated pool data    0.00%
   Allocated metadata     11.23%
   Current LE             125
   Segments               1
   Allocation             inherit
   Read ahead sectors     auto
 currently set to     8192
 Block device           253:5
 --- Logical volume ---
 LV Path                /dev/vg_thin/tp_lv_user1
 LV Name                tp_lv_user1
 VG Name                vg_thin
 LV UUID                iVUkmG-c4qA-dLSe-XIG3-zAUF-UKFT-n5tGAu
 LV Write Access        read/write
 LV Creation host, time fileserver, 2019-08-30 04:12:38 +0300
 LV Pool name           tp_pool
 LV Status              available
 open                 0
 LV Size                100.00 MiB
 Mapped size            0.00%
 Current LE             25
 Segments               1
 Allocation             inherit
 Read ahead sectors     auto
 currently set to     8192
 Block device           253:7
 --- Logical volume ---
 LV Path                /dev/vg_thin/tp_lv_user2
 LV Name                tp_lv_user2
 VG Name                vg_thin
 LV UUID                4NKRLc-lwA8-cM1j-g791-g2Kj-iP54-GfWOI6
 LV Write Access        read/write
 LV Creation host, time fileserver, 2019-08-30 04:12:39 +0300
 LV Pool name           tp_pool
 LV Status              available
 open                 0
 LV Size                100.00 MiB
 Mapped size            0.00%
 Current LE             25
 Segments               1
 Allocation             inherit
 Read ahead sectors     auto
 currently set to     8192
 Block device           253:8
 --- Logical volume ---
 LV Path                /dev/vg_thin/tp_lv_user3
 LV Name                tp_lv_user3
 VG Name                vg_thin
 LV UUID                avO0OQ-lHVI-dPXK-vjuD-Jmlk-sRNq-X5Lhsj
 LV Write Access        read/write
 LV Creation host, time fileserver, 2019-08-30 04:12:39 +0300
 LV Pool name           tp_pool
 LV Status              available
 open                 0
 LV Size                100.00 MiB
 Mapped size            0.00%
 Current LE             25
 Segments               1
 Allocation             inherit
 Read ahead sectors     auto
 currently set to     8192
 Block device           253:9
 --- Logical volume ---
 LV Path                /dev/vg_thin/tp_lv_user4
 LV Name                tp_lv_user4
 VG Name                vg_thin
 LV UUID                Vib4RM-naEd-su52-tY9h-WZAE-6Pot-2EXPHk
 LV Write Access        read/write
 LV Creation host, time fileserver, 2019-08-30 04:12:40 +0300
 LV Pool name           tp_pool
 LV Status              available
 open                 0
 LV Size                100.00 MiB
 Mapped size            0.00%
 Current LE             25
 Segments               1
 Allocation             inherit
 Read ahead sectors     auto
 currently set to     8192
 Block device           253:10 
 [root@fileserver ~]#

Once you have copied some file rerun this command and notice the Allocated pool data and Mapped Size you should get some values.

FileSystem and Mounting

Create the filesystem on those thin volumes.

# mkfs.xfs /dev/mapper/vg_thin-tp_lv_user1
# mkfs.xfs /dev/mapper/vg_thin-tp_lv_user2
# mkfs.xfs /dev/mapper/vg_thin-tp_lv_user3
# mkfs.xfs /dev/mapper/vg_thin-tp_lv_user4

Create directories to mount the filesystems.

# mkdir /mnt/user{1..4}/
# ls -lthr /mnt/

Mount the file system under created mount points.

# mount /dev/mapper/vg_thin-tp_lv_user1 /mnt/user1/
# mount /dev/mapper/vg_thin-tp_lv_user2 /mnt/user2/
# mount /dev/mapper/vg_thin-tp_lv_user3 /mnt/user3/
# mount /dev/mapper/vg_thin-tp_lv_user4 /mnt/user4/

Verify the size, we should get all with the same size and none of data’s is residing under new mount points.

[root@fileserver ~]# df -hP /mnt/user*
 Filesystem                       Size  Used Avail Use% Mounted on
 /dev/mapper/vg_thin-tp_lv_user1   97M  5.3M   92M   6% /mnt/user1
 /dev/mapper/vg_thin-tp_lv_user2   97M  5.3M   92M   6% /mnt/user2
 /dev/mapper/vg_thin-tp_lv_user3   97M  5.3M   92M   6% /mnt/user3
 /dev/mapper/vg_thin-tp_lv_user4   97M  5.3M   92M   6% /mnt/user4
[root@fileserver ~]#

Try to copy some files and fill with the random size, Now once again verify.

[root@fileserver ~]# df -hP /mnt/user*
 Filesystem                       Size  Used Avail Use% Mounted on
 /dev/mapper/vg_thin-tp_lv_user1   97M   56M   42M  57% /mnt/user1
 /dev/mapper/vg_thin-tp_lv_user2   97M   81M   17M  83% /mnt/user2
 /dev/mapper/vg_thin-tp_lv_user3   97M   46M   52M  47% /mnt/user3
 /dev/mapper/vg_thin-tp_lv_user4   97M   66M   32M  68% /mnt/user4
[root@fileserver ~]#

Now run lvs command to verify the pool and volume utilization.

# lvs

The values have been changed after we copied a few files under all four mount points. We can notice the thin pool utilization have 47.67% so it’s almost half of pool size has been utilized.

Listing with files in Thinly Provisioned Logical volume
Listing with files
  1. The leading V means its a Volume or thin volume.
  2. Size of the Thin volume.
  3. Data consumption under the thin volume.
  4. The total size of the thin pool usage.
  5. Metadata usage under the thin pool.

Over Provisioning

Without Over-Provisioning Protection

Create two more 100 MB for new users. While we create more thin volumes from the same thin pool than it’s allocated size it will have more risk and throw a few warning to show you as overprovisioning.

# lvcreate -V 100M --thin -n tp_lv_user5 vg_thin/tp_pool
# lvcreate -V 100M --thin -n tp_lv_user6 vg_thin/tp_pool

Output for reference

[root@fileserver ~]# lvcreate -V 100M --thin -n tp_lv_user6 vg_thin/tp_pool
   WARNING: Sum of all thin volume sizes (600.00 MiB) exceeds the size of thin pool vg_thin/tp_pool and the amount of free space in volume group (512.00 MiB).
   WARNING: You have not turned on protection against thin pools running out of space.
   WARNING: Set activation/thin_pool_autoextend_threshold below 100 to trigger automatic extension of thin pools before they get full.
  Logical volume "tp_lv_user6" created.

Newly created thin volumes.

[root@fileserver ~]# df -hP /mnt/user*
 Filesystem                       Size  Used Avail Use% Mounted on
 /dev/mapper/vg_thin-tp_lv_user1   97M   56M   42M  57% /mnt/user1
 /dev/mapper/vg_thin-tp_lv_user2   97M   81M   17M  83% /mnt/user2
 /dev/mapper/vg_thin-tp_lv_user3   97M   46M   52M  47% /mnt/user3
 /dev/mapper/vg_thin-tp_lv_user4   97M   66M   32M  68% /mnt/user4
 /dev/mapper/vg_thin-tp_lv_user5   97M  5.3M   92M   6% /mnt/user5
 /dev/mapper/vg_thin-tp_lv_user6   97M  5.3M   92M   6% /mnt/user6
[root@fileserver ~]#

Copy some files to newly created thin volumes.

[root@fileserver ~]# df -hP /mnt/user*
 Filesystem                       Size  Used Avail Use% Mounted on
 /dev/mapper/vg_thin-tp_lv_user1   97M   56M   42M  57% /mnt/user1
 /dev/mapper/vg_thin-tp_lv_user2   97M   81M   17M  83% /mnt/user2
 /dev/mapper/vg_thin-tp_lv_user3   97M   46M   52M  47% /mnt/user3
 /dev/mapper/vg_thin-tp_lv_user4   97M   66M   32M  68% /mnt/user4
 /dev/mapper/vg_thin-tp_lv_user5   97M   61M   37M  63% /mnt/user5
 /dev/mapper/vg_thin-tp_lv_user6   97M   16M   82M  16% /mnt/user6
[root@fileserver ~]#

Then verify the thin pool utilization by running lvs command. Still, we can notice the total utilization is 62.03%.

Thin-Pool-Over-Provisioning
Thin Pool Over Provisioning

From the above snip, we can understand that over-provisioning is something we can provide more than what we actually have. The steps we followed have more risk of losing data if you are not keeping a (monitoring) eye on it.

With Over-Provisioning Protection

Configure Over-Provisioning protection

We can protect the thin pools while running out of space by configuring lvm.conf.

# vim /etc/lvm/lvm.conf

Auto-extend a thin pool when its usage exceeds this percentage, Changing this to 100 disables the automatic extension. The accepted minimum value is 50.

thin_pool_autoextend_threshold = 80

While over-provisioning we should not face any issue, By auto extending a thin pool adds this percentage extra space. The amount of additional space added to a thin pool is this percentage of its current size.

thin_pool_autoextend_percent = 20

For example, Using 80% auto-extend threshold and 20% auto-extend size, when a 500 MB thin pool exceeds 400M, it is extended to 600 MB., and when it exceeds 480M, it is extended to (+20%) 800 MB.

Create Thin Volumes with Over-Provisioning Protection

This is the size of Volume group free space we have before creating more thin volumes.

[root@fileserver ~]# vgs
   VG      #PV #LV #SN Attr   VSize    VFree  
   centos    1   3   0 wz--n-  <99.00g   4.00m
   vg_thin   1   7   0 wz--n- 1020.00m 512.00m
 [root@fileserver ~]#

Let’s create two more thin volumes.

[root@fileserver ~]# lvcreate -V 100M --thin -n tp_lv_user5 vg_thin/tp_pool
   Logical volume "tp_lv_user5" created.
 [root@fileserver ~]# lvcreate -V 100M --thin -n tp_lv_user6 vg_thin/tp_pool
   WARNING: Sum of all thin volume sizes (600.00 MiB) exceeds the size of thin pool vg_thin/tp_pool and the amount of free space in volume group (512.00 MiB).
   Logical volume "tp_lv_user6" created.
[root@fileserver ~]#

And create the filesystem on those new thin volumes.

# mkfs.xfs /dev/mapper/vg_thin-tp_lv_user5
# mkfs.xfs /dev/mapper/vg_thin-tp_lv_user6

List and verify the current thin pool and thin volumes. As usual, Thin pool remains the same size and newly created thin volume not yet filled with data’s.

[root@fileserver ~]# lvs
   LV          VG      Attr       LSize   Pool    Origin Data%  Meta%  Move Log Cpy%Sync Convert
   home        centos  -wi-ao----  46.99g                                                       
   root        centos  -wi-ao----  50.00g                                                       
   swap        centos  -wi-ao----   2.00g                                                       
   tp_lv_user1 vg_thin Vwi-aotz-- 100.00m tp_pool        53.31                                  
   tp_lv_user2 vg_thin Vwi-aotz-- 100.00m tp_pool        78.31                                  
   tp_lv_user3 vg_thin Vwi-aotz-- 100.00m tp_pool        43.44                                  
   tp_lv_user4 vg_thin Vwi-aotz-- 100.00m tp_pool        63.31                                  
   tp_lv_user5 vg_thin Vwi-a-tz-- 100.00m tp_pool        0.00                                   
   tp_lv_user6 vg_thin Vwi-a-tz-- 100.00m tp_pool        0.00                                   
   tp_pool     vg_thin twi-aotz-- 500.00m                47.67  13.87

Fill with some files to the newly created thin volumes.

[root@fileserver ~]# df -hP
 Filesystem                       Size  Used Avail Use% Mounted on
 /dev/mapper/centos-root           50G  1.4G   49G   3% /
 devtmpfs                         411M     0  411M   0% /dev
 tmpfs                            423M     0  423M   0% /dev/shm
 tmpfs                            423M  6.8M  416M   2% /run
 tmpfs                            423M     0  423M   0% /sys/fs/cgroup
 /dev/sda1                       1014M  186M  829M  19% /boot
 /dev/mapper/centos-home           47G   33M   47G   1% /home
 tmpfs                             85M     0   85M   0% /run/user/0
 /dev/mapper/vg_thin-tp_lv_user1   97M   56M   42M  57% /mnt/user1
 /dev/mapper/vg_thin-tp_lv_user2   97M   81M   17M  83% /mnt/user2
 /dev/mapper/vg_thin-tp_lv_user3   97M   46M   52M  47% /mnt/user3
 /dev/mapper/vg_thin-tp_lv_user4   97M   66M   32M  68% /mnt/user4
 /dev/mapper/vg_thin-tp_lv_user5   97M   97M  800K 100% /mnt/user5
 /dev/mapper/vg_thin-tp_lv_user6   97M   91M  6.7M  94% /mnt/user6

Once we fill with some files, The growth of thin pool utilization increases and reached 80%. So our thin pool size will be extended +20% automatically from the available Volume Group free space. Run vgs to confirm the VG size now.

[root@fileserver ~]# vgs
   VG      #PV #LV #SN Attr   VSize    VFree  
   centos    1   3   0 wz--n-  <99.00g   4.00m
   vg_thin   1   7   0 wz--n- 1020.00m 412.00m
[root@fileserver ~]#

Now check the size of the thin pool it should be higher than before. Moreover, these changes automatically kicked in to protect the over-provisioning. Thus the protected over-provisioning work on a Thinly Provisioned Logical volume.

[root@fileserver ~]# lvs
   LV          VG      Attr       LSize   Pool    Origin Data%  Meta%  Move Log Cpy%Sync Convert
   home        centos  -wi-ao----  46.99g                                                       
   root        centos  -wi-ao----  50.00g                                                       
   swap        centos  -wi-ao----   2.00g                                                       
   tp_lv_user1 vg_thin Vwi-aotz-- 100.00m tp_pool        53.31                                  
   tp_lv_user2 vg_thin Vwi-aotz-- 100.00m tp_pool        78.31                                  
   tp_lv_user3 vg_thin Vwi-aotz-- 100.00m tp_pool        43.44                                  
   tp_lv_user4 vg_thin Vwi-aotz-- 100.00m tp_pool        63.31                                  
   tp_lv_user5 vg_thin Vwi-aotz-- 100.00m tp_pool        94.31                                  
   tp_lv_user6 vg_thin Vwi-aotz-- 100.00m tp_pool        88.31                                  
   tp_pool     vg_thin twi-aotz-- 600.00m                70.17  15.72                           
[root@fileserver ~]#

How to Extend a Thin Pool

There are two steps we need to follow while extending a thin pool

  1. Extend the thin pool’s metadata
  2. Then extend the Thin Pool.

To extend a thin pool we should not go ahead straight away to extend the thin pool. First, check the size of existing metadata usage by running lvs command with “-a” option.

[root@fileserver ~]# lvs -a
   LV              VG      Attr       LSize   Pool    Origin Data%  Meta%  Move Log Cpy%Sync Convert
   home            centos  -wi-ao----  46.99g                                                       
   root            centos  -wi-ao----  50.00g                                                       
   swap            centos  -wi-ao----   2.00g                                                       
   [lvol0_pmspare] vg_thin ewi-------   4.00m                                                       
   tp_lv_user1     vg_thin Vwi-a-tz-- 100.00m tp_pool        59.31                                  
   tp_lv_user2     vg_thin Vwi-a-tz-- 100.00m tp_pool        95.12                                  
   tp_lv_user3     vg_thin Vwi-a-tz-- 100.00m tp_pool        43.44                                  
   tp_lv_user4     vg_thin Vwi-a-tz-- 100.00m tp_pool        95.06                                  
   tp_lv_user5     vg_thin Vwi-a-tz-- 100.00m tp_pool        58.31                                  
   tp_lv_user6     vg_thin Vwi-a-tz-- 100.00m tp_pool        95.06                                  
   tp_pool         vg_thin twi-aotz-- 600.00m                74.39  16.11                           
   [tp_pool_tdata] vg_thin Twi-ao---- 600.00m                                                       
   [tp_pool_tmeta] vg_thin ewi-ao----   4.00m                                                       
[root@fileserver ~]#

Here, we can notice metadata size at the last line.

Extend the Metadata Size.

The current usage of metadata is just 4 MB. Let us add more + 4MB from the current size.

# lvextend --poolmetadatasize +4M vg_thin/tp_pool

Look at the below output for metadata changes from 4 MB to 8 MB.

[root@fileserver ~]# lvextend --poolmetadatasize +4M vg_thin/tp_pool
   Size of logical volume vg_thin/tp_pool_tmeta changed from 4.00 MiB (1 extents) to 8.00 MiB (2 extents).
   Logical volume vg_thin/tp_pool_tmeta successfully resized.
[root@fileserver ~]#

Once again run lvs command with the option to verify the metadata.

[root@fileserver ~]# lvs -a
   LV              VG      Attr       LSize   Pool    Origin Data%  Meta%  Move Log Cpy%Sync Convert
   home            centos  -wi-ao----  46.99g                                                       
   root            centos  -wi-ao----  50.00g                                                       
   swap            centos  -wi-ao----   2.00g                                                       
   [lvol0_pmspare] vg_thin ewi-------   4.00m                                                       
   tp_lv_user1     vg_thin Vwi-a-tz-- 100.00m tp_pool        59.31                                  
   tp_lv_user2     vg_thin Vwi-a-tz-- 100.00m tp_pool        95.12                                  
   tp_lv_user3     vg_thin Vwi-a-tz-- 100.00m tp_pool        43.44                                  
   tp_lv_user4     vg_thin Vwi-a-tz-- 100.00m tp_pool        95.06                                  
   tp_lv_user5     vg_thin Vwi-a-tz-- 100.00m tp_pool        58.31                                  
   tp_lv_user6     vg_thin Vwi-a-tz-- 100.00m tp_pool        95.06                                  
   tp_pool         vg_thin twi-aotz-- 600.00m                74.39  13.04                           
   [tp_pool_tdata] vg_thin Twi-ao---- 600.00m                                                       
   [tp_pool_tmeta] vg_thin ewi-ao----   8.00m                                                       
[root@fileserver ~]#

After the extension, we should see 8 MB as metadata size.

Extend the Thin Pool size.

Once completed with extending the metadata start to extend the thin pool to your desired size available from the volume group. We are trying with extending from current size 600 MB to 700 MB.

# lvextend -L +100M /dev/vg_thin/tp_pool

For your reference

[root@fileserver ~]# lvextend -L +100M /dev/vg_thin/tp_pool 
   Size of logical volume vg_thin/tp_pool_tdata changed from 600.00 MiB (150 extents) to 700.00 MiB (175 extents).
   Logical volume vg_thin/tp_pool_tdata successfully resized.
[root@fileserver ~]#

This is the current size of the thin pool after extension.

[root@fileserver ~]# lvs
   LV          VG      Attr       LSize   Pool    Origin Data%  Meta%  Move Log Cpy%Sync Convert
   home        centos  -wi-ao----  46.99g                                                       
   root        centos  -wi-ao----  50.00g                                                       
   swap        centos  -wi-ao----   2.00g                                                       
   tp_lv_user1 vg_thin Vwi-a-tz-- 100.00m tp_pool        59.31                                  
   tp_lv_user2 vg_thin Vwi-a-tz-- 100.00m tp_pool        95.12                                  
   tp_lv_user3 vg_thin Vwi-a-tz-- 100.00m tp_pool        43.44                                  
   tp_lv_user4 vg_thin Vwi-a-tz-- 100.00m tp_pool        95.06                                  
   tp_lv_user5 vg_thin Vwi-a-tz-- 100.00m tp_pool        58.31                                  
   tp_lv_user6 vg_thin Vwi-a-tz-- 100.00m tp_pool        95.06                                  
   tp_pool     vg_thin twi-aotz-- 700.00m                63.76  13.04                           
[root@fileserver ~]#

If you need more space in the volume group its usual step as mentioned in this guide.


How to Remove a Thin Pool

To remove a thin pool first we need to unmount all the filesystem, then remove all thin volumes, finally remove the thin pool.

# lvremove -y /dev/vg_thin/tp_lv_user[1-6]

We are removing all thin volumes in a single go.

[root@fileserver ~]# lvremove -y /dev/vg_thin/tp_lv_user[1-6]
   Logical volume "tp_lv_user1" successfully removed
   Logical volume "tp_lv_user2" successfully removed
   Logical volume "tp_lv_user3" successfully removed
   Logical volume "tp_lv_user4" successfully removed
   Logical volume "tp_lv_user5" successfully removed
   Logical volume "tp_lv_user6" successfully removed
[root@fileserver ~]#

By following, remove the thin pool using lvremove.

# lvremove /dev/vg_thin/tp_pool 

If you have a number of thin pools make sure to remove the correct one.

[root@fileserver ~]# lvremove /dev/vg_thin/tp_pool 
 Do you really want to remove active logical volume vg_thin/tp_pool? [y/n]: y
  Logical volume "tp_pool" successfully removed
[root@fileserver ~]#

Finally, verify running lvs and vgs commands.

[root@fileserver ~]# lvs
   LV   VG     Attr       LSize  Pool Origin Data%  Meta%  Move Log Cpy%Sync Convert
   home centos -wi-ao---- 46.99g                                                    
   root centos -wi-ao---- 50.00g                                                    
   swap centos -wi-ao----  2.00g                                                    
[root@fileserver ~]#

[root@fileserver ~]# vgs
   VG      #PV #LV #SN Attr   VSize    VFree   
   centos    1   3   0 wz--n-  <99.00g    4.00m
   vg_thin   1   0   0 wz--n- 1020.00m 1020.00m
[root@fileserver ~]#

That’s it, we have successfully completed with working on Thinly Provisioned Logical volume.

Conclusion

Logical volume management is one of the coolest concepts in Linux. The Thinly Provisioned Logical volume is one of the advanced storage feature supported under LVM. Subscribe to our newsletter for more guides and stay closer to us. Your feedbacks are most welcome through below comment section.

LEAVE A REPLY

Please enter your comment!
Please enter your name here