Design Hard Disk Layout LVM

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What You’ll Learn

• Installing LVM utilities
• Key LVM components: PV, VG, LV, PE
• Creating Physical Volumes (PV)
• Building and extending Volume Groups (VG)
• Allocating and resizing Logical Volumes (LV)
• Formatting and resizing filesystems
• Common commands and handy tips

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Prerequisites

sudo dnf install lvm2

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LVM Abbreviations

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1. Creating Physical Volumes (PV)

1. Scan for available disks and existing PVs:
   sudo lvmdiskscan
   
   Sample output:
   /dev/sda1  [   1.00 GiB]
   /dev/sda2  [ <19.00 GiB] LVM physical volume
   /dev/sdb1  [   4.00 GiB]
   /dev/sdc   [   5.00 GiB]
   /dev/sdd   [   5.00 GiB]
   /dev/sde   [   5.00 GiB]
   3 disks
   1 LVM physical volume
   
2. Initialize /dev/sdc and /dev/sdd as new PVs:
   sudo pvcreate /dev/sdc /dev/sdd
   
3. Verify all PVs:
   sudo pvs
   
     PV         VG         Fmt  Attr PSize   PFree
     /dev/sda2  cs         lvm2 a--  <19.00g    0
     /dev/sdc   lvm2 ---   5.00g  5.00g
     /dev/sdd   lvm2 ---   5.00g  5.00g
   

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2. Building a Volume Group (VG)

1. Create a VG named my_volume:
   sudo vgcreate my_volume /dev/sdc /dev/sdd
   
   Volume group "my_volume" successfully created
   
2. To extend the VG later, initialize another PV:
   sudo pvcreate /dev/sde
   
3. Add it to my_volume:
   sudo vgextend my_volume /dev/sde
   
4. List all VGs:
   sudo vgs
   
     VG          #PV #LV #SN Attr   VSize   VFree
     cs           1   2   0 wz--n  <19.00g    0
     my_volume    3   0   0 wz--n  14.99g 14.99g
   

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Removing a PV from a VG

1. Detach /dev/sde:
   sudo vgreduce my_volume /dev/sde
   
2. Wipe its metadata:
   sudo pvremove /dev/sde
   

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3. Allocating Logical Volumes (LV)

1. Create a 2 GiB LV called partition1:
   sudo lvcreate --size 2G --name partition1 my_volume
   
2. Create a 6 GiB LV called partition2:
   sudo lvcreate --size 6G --name partition2 my_volume
   
3. View all LVs:
   sudo lvs
   
     LV         VG         Attr       LSize
     partition1 my_volume -wi-a----- 2.00g
     partition2 my_volume -wi-a----- 6.00g
   
4. Check remaining VG space:
   sudo vgs
   
     VG         #PV #LV #SN Attr   VSize   VFree
     my_volume   2   2   0 wz--n-  9.99g  1.99g
   

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4. Resizing Logical Volumes

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Grow to Fill Free Space

sudo lvresize --extents +100%FREE /dev/my_volume/partition1

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Shrink Back

sudo lvresize --size 2G /dev/my_volume/partition1

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5. Formatting the Filesystem

sudo mkfs.xfs /dev/my_volume/partition1

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6. Resizing with an Existing Filesystem

sudo lvresize --resizefs --size 3G /dev/my_volume/partition1

Note: Not all filesystems support online shrinking. Check your filesystem’s documentation.

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7. Handy Tips & Resources

• Browse the full LVM manual:
  man lvm
  
• Use tab-completion to explore subcommands:
  vg↹↹
  
• Always back up critical data before performing volume operations.

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Links and References

• LVM Documentation
• mkfs.xfs Man Page
• KVM Virtual Disks