Linux LVM, RAID, and Encryption Cheat Sheet

sudo pvcreate /dev/sdb1

# Prepare a partition or whole device for LVM use.

sudo pvs

# Compact overview of LVM physical volumes.

sudo pvdisplay

# Verbose physical volume information including UUID and extents.

sudo vgcreate vgdata /dev/sdb1

# Create a VG from one or more initialized PVs.

sudo vgs

# Compact view of VGs, free extents, and sizes.

sudo vgdisplay vgdata

# Verbose VG information including free space and metadata.

sudo lvcreate -L 100G -n lvdata vgdata

# Allocate a fixed-size LV from a volume group.

sudo lvcreate -l 100%FREE -n lvdata vgdata

# Use all remaining free extents in the VG.

sudo lvs

# Preferred compact overview of logical volumes and attributes.

sudo lvdisplay /dev/vgdata/lvdata

# Verbose LV information including path and size.

sudo mkfs.ext4 /dev/vgdata/lvdata

# Format a new logical volume for use.

sudo mount /dev/vgdata/lvdata /mnt/data

# Mount an LV like any other block device.

sudo vgextend vgdata /dev/sdc1

# Increase free capacity in a volume group.

sudo lvextend -L +50G /dev/vgdata/lvdata

# Grow the logical volume size.

sudo lvextend -r -L +50G /dev/vgdata/lvdata

# Grow both the LV and the contained filesystem when supported.

sudo resize2fs /dev/vgdata/lvdata

# Expand an ext filesystem to fill the larger LV.

sudo xfs_growfs /mnt/data

# Expand an XFS filesystem using the mounted path.

sudo lvreduce -L 50G /dev/vgdata/lvdata

# Dangerous if done without shrinking the filesystem first.

sudo resize2fs /dev/vgdata/lvdata 45G

# For ext filesystems, shrink the filesystem before shrinking the LV.

sudo lvcreate -L 10G -s -n lvdata_snap /dev/vgdata/lvdata

# Create a snapshot LV for backup or rollback workflows.

sudo lvremove /dev/vgdata/lvdata_snap

# Delete an unneeded LVM snapshot.

sudo pvmove /dev/sdb1

# Relocate data to other PVs before removing a disk.

sudo vgreduce vgdata /dev/sdb1

# Detach an empty or evacuated PV from a VG.

sudo lvremove /dev/vgdata/lvdata

# Remove an LV and return space to the VG.

sudo mdadm --create /dev/md0 --level=1 --raid-devices=2 /dev/sdb1 /dev/sdc1

# Create a mirrored software RAID device.

sudo mdadm --create /dev/md0 --level=5 --raid-devices=3 /dev/sdb1 /dev/sdc1 /dev/sdd1

# Create a RAID5 array with striping and parity.

cat /proc/mdstat

# Quick view of RAID sync, rebuild, and degraded state.

sudo mdadm --detail /dev/md0

# Inspect RAID level, members, and rebuild progress.

sudo mdadm --examine /dev/sdb1

# Inspect md superblock metadata directly on a member device.

sudo mdadm --stop /dev/md0

# Stop a software RAID device before disassembly or recovery work.

sudo mdadm --assemble --scan

# Discover and assemble arrays based on metadata or config.

sudo mdadm --detail --scan | sudo tee -a /etc/mdadm/mdadm.conf

# Persist discovered arrays into mdadm configuration.

sudo cryptsetup luksFormat /dev/sdb1

# Create a LUKS-encrypted block device.

sudo cryptsetup open /dev/sdb1 cryptdata

# Map an encrypted device to /dev/mapper/cryptdata.

sudo cryptsetup close cryptdata

# Lock and remove the decrypted device mapping.

lsblk -o NAME,SIZE,TYPE,FSTYPE,MOUNTPOINTS

# Verify decrypted mapper devices and mountpoints.