Partitioning destroys data on selected disks. Back up Windows and personal files before resizing. Double-check device names with lsblk — /dev/sda is not always the disk you think it is.
What you will achieve
Plan a UEFI-friendly partition layout for Ubuntu or Debian so install, upgrades, and dual-boot with Windows work without fighting the bootloader later.
1) UEFI requires GPT, not MBR
Modern PCs boot via UEFI firmware. Use a GUID Partition Table (GPT) on the target disk. Legacy BIOS installs use MBR — mixing them on the same UEFI machine causes GRUB headaches.
sudo parted /dev/nvme0n1 print
# Partition Table: gpt confirms GPT2) The EFI System Partition (ESP)
UEFI firmware reads boot loaders from a FAT32 ESP. Ubuntu's installer creates one automatically; for manual partitioning, allocate 512 MB to 1 GB, type EFI System Partition, mount at /boot/efi.
sudo mkfs.vfat -F 32 /dev/nvme0n1p1
# Mount point in installer: /boot/efiIf dual-booting Windows, reuse the existing ESP — do not format it unless you enjoy rebuilding the Windows boot entry.
3) Root filesystem: ext4 vs btrfs
Ubuntu defaults to ext4 on / — reliable, well supported, easy to resize. btrfs adds snapshots (Timeshift-friendly) but needs more care on older kernels. For a first install, ext4 with 30–80 GB root is sensible; keep home on a separate partition if you dual-boot often.
4) Swap on modern systems
With 16 GB RAM or more, a small swap partition (2–4 GB) or swap file is enough for hibernate-free setups. Ubuntu 24.04 can use zswap. Separate swap partition simplifies hibernation if you need it.
# Example layout (adjust sizes):
# ESP 512 MB FAT32 /boot/efi
# swap 4 GB swap
# root 60 GB ext4 /
# home rest ext4 /home5) Dual-boot headroom
Shrink Windows from Disk Management (or ntfsresize from a live session) before install. Leave unallocated space for the Linux installer — do not create Linux partitions from Windows unless you know what you are doing. Install Linux after Windows so GRUB detects both OS entries.
6) LVM optional layer
Ubuntu offers LVM during install for flexible volume growth. Useful on servers; optional on desktops. Plain partitions are simpler to recover if something goes wrong.
Verify
lsblk -f
efibootmgr -vConfirm ESP is FAT32, root is mounted, and UEFI boot entries list ubuntu or debian after install.