Many sysadmins discover LVM's benefits (like volume resizing, snapshots, and flexible storage pools) only after setting up traditional partitions. The good news: conversion is possible without reinstalling your system, though it requires careful execution.

Before proceeding, ensure you have:

• A complete backup of all critical data

• A live USB/CD for emergency recovery

• At least 20% free space on your source partitions

• Understanding of your current partition layout (lsblk -f and fdisk -l)

Here's the technical workflow I've used successfully on Debian/Ubuntu systems. For RHEL/CentOS, adjust package names accordingly:

# Install necessary tools
sudo apt install lvm2

# Create physical volume on target disk
sudo pvcreate /dev/sdaX

# Create volume group
sudo vgcreate vg0 /dev/sdaX

# Create logical volumes matching your current setup
sudo lvcreate -L 20G -n root vg0
sudo lvcreate -L 8G -n home vg0
sudo lvcreate -L 2G -n swap vg0

# Format the new volumes
sudo mkfs.ext4 /dev/vg0/root
sudo mkfs.ext4 /dev/vg0/home
sudo mkswap /dev/vg0/swap

For the actual data transfer, I prefer rsync for its reliability:

# Mount both source and destination
sudo mkdir /mnt/{old,new}
sudo mount /dev/sdaY /mnt/old
sudo mount /dev/vg0/root /mnt/new

# Copy data preserving permissions
sudo rsync -aAXv /mnt/old/ /mnt/new/

Critical post-migration steps:

# Update fstab with new UUIDs
sudo blkid /dev/vg0/root >> /etc/fstab
sudo blkid /dev/vg0/home >> /etc/fstab

# For GRUB2 systems:
sudo grub-install /dev/sda
sudo update-grub

Your assumption is correct - Windows cannot natively access LVM volumes. For shared partitions:

• Keep Windows-accessible partitions as standard NTFS/FAT32
• Consider creating a separate non-LVM ext4 partition for Linux-Windows file sharing

Always test your new setup before deleting old partitions:

# Check LVM status
sudo vgdisplay
sudo lvdisplay

# Verify filesystem integrity
sudo fsck /dev/vg0/root

Common pitfalls include forgetting to update initramfs (update-initramfs -u) or incorrect fstab entries. Always have a recovery plan.

Many sysadmins who discovered LVM's benefits (like myself) face a common dilemma - how to migrate existing traditional partitions to LVM without reinstalling the entire system. While challenging, it's absolutely possible with careful planning and execution.

Before beginning, ensure you have:

• Backup of all critical data (mandatory)
• Live CD/USB with LVM tools (Ubuntu/Debian live images work well)
• Enough free space (either unpartitioned or shrinkable)
• Basic understanding of LVM concepts (PVs, VGs, LVs)

Here's the technical workflow I've successfully used:

# 1. Boot into live environment
sudo -i
fdisk -l # identify current partitions

# 2. Create physical volume on target disk
pvcreate /dev/sdaX

# 3. Create volume group
vgcreate vg0 /dev/sdaX

# 4. Create logical volumes matching original partition sizes
lvcreate -L 20G -n root vg0
lvcreate -L 8G -n home vg0
lvcreate -L 2G -n swap vg0

# 5. Create filesystems on new LVs
mkfs.ext4 /dev/vg0/root
mkfs.ext4 /dev/vg0/home
mkswap /dev/vg0/swap

The critical phase - copying data without corruption:

# Mount both source and target
mkdir /mnt/{src,dest}
mount /dev/sdaY /mnt/src # source partition
mount /dev/vg0/root /mnt/dest

# Rsync for reliable transfer
rsync -aAXv /mnt/src/* /mnt/dest/

# Verify checksums (example for /etc)
find /mnt/src/etc -type f -exec md5sum {} + > /tmp/src.md5
find /mnt/dest/etc -type f -exec md5sum {} + > /tmp/dest.md5
diff /tmp/src.md5 /tmp/dest.md5

After migration, update your bootloader:

# For GRUB2:
mount --bind /dev /mnt/dest/dev
mount --bind /proc /mnt/dest/proc
mount --bind /sys /mnt/dest/sys
chroot /mnt/dest
grub-install /dev/sda
update-grub

Regarding your Windows dual-boot question:

• Windows cannot natively read LVM volumes
• Shared NTFS partitions must remain as basic partitions
• Consider keeping /boot as standard partition if using GRUB

After successful conversion, you gain:

• Online resizing capabilities
• Snapshot functionality
• Easier storage management
• Better disk utilization

Common issues and solutions:

# If system fails to boot:
1. Check /etc/fstab entries match new LVs
2. Verify initramfs includes LVM modules:
   lsinitramfs /boot/initrd.img-$(uname -r) | grep lvm

# Regenerate initramfs if needed:
update-initramfs -u -k all