Installation Storage

Storage & Encryption

These two steps decide where RetroLinux goes (which disk) and how it protects your data (LUKS encryption).

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Step 11 · Disk selection

This is the most important step. You pick which disk to install RetroLinux onto.

• The installer lists all available disks with their size.
• Select one; if the disk already has partitions, you get a clear warning: all data on this disk will be ERASED to set up BTRFS. You must confirm "I understand, continue".

Note

What is BTRFS?

RetroLinux installs on BTRFS, the default filesystem. If you are coming from Windows (NTFS) or a plain Linux setup (ext4), here is what that means in plain terms.

A filesystem is how your disk stores files. BTRFS is a modern, copy-on-write filesystem that RetroLinux uses because it is:

• Fast — data is compressed on the fly with zstd, so it writes less and reads faster on most disks.
• Reliable — checksums every block, so silent data corruption is detected and reported instead of going unnoticed.
• Snapshot-friendly — BTRFS snapshots are instant and take almost no extra space. This is what powers Timeshift: RetroLinux takes automatic snapshots and puts them right in the GRUB boot menu, so if you ever break something you can boot straight into a previous working state and roll back.
• Encryption-friendly — it layers cleanly with LUKS encryption, so you get the safety of encryption and snapshots at the same time.

The installer splits the disk into subvolumes (@, @home, @log, @pkg) — separate folders with their own mount points, which makes rollbacks and backups much cleaner. Everything happens automatically during install; you do not need to know any of this to use it.

Want the deep dive? The Arch Wiki BTRFS article covers subvolumes, snapshots, compression, and everything else in detail.

Warning

This step erases everything on the selected disk. Double-check the disk name and size before confirming. There is no undo.

If you decline the wipe confirmation, the installer goes back so you can pick a different disk.

The disk name is stored as DISK_SELECTED (for example /dev/sda) and used by the configuration step to build the partition layout.

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Step 12 · Disk encryption (LUKS)

You can enable LUKS encryption to protect your data at rest, if your laptop is stolen, the drive contents stay unreadable without the password.

Note

What is LUKS?

LUKS (Linux Unified Key Setup) is the standard for disk encryption on Linux. If your laptop or drive is lost or stolen, an attacker cannot read your files without the password — the data is scrambled and only decryptable with the right key.

Here is how it works in plain terms:

• Encryption happens at the block level. LUKS wraps the whole disk (or partition) in an encrypted container. Everything written to it is scrambled on the fly, so the filesystem inside (here, BTRFS) stores only ciphertext. You cannot see file names, sizes, or contents without unlocking it first.
• One password unlocks it, but it is not the key itself. When you set the LUKS password, the installer generates a random master key and encrypts that key with your password. This is why changing your password later is instant — it only re-encrypts the master key, not the whole disk.
• It layers cleanly with BTRFS. Encryption happens below the filesystem: LUKS wraps the disk, BTRFS lives inside the unlocked container. That means you still get BTRFS snapshots, compression, and Timeshift rollbacks on top of full-disk encryption — the best of both.
• You unlock it at boot. After GRUB loads, you type your LUKS password before the system starts. Only then is the disk decrypted and the OS booted. If you forget it, the data stays locked.

Because the encryption key is derived from your password, its strength depends on both the password and how long key derivation takes — that is exactly what the iteration time setting below controls.

Want the deep dive? The Arch Wiki LUKS article covers the cryptsetup flow, key slots, and everything else in detail.

Tip

Encryption is strongly recommended, especially on laptops. If you encrypt, you must enter this password at every boot before the system starts.

Warning

If you enable LUKS, hibernation will not work. Hibernation writes your RAM to the swap disk and restores it on next boot, but with encryption the swap image is unreadable before the LUKS password is entered. Instead of hibernating, encrypted systems use suspend to RAM (sleep), which keeps your session in memory and is fine to use.

Password

If you already created a user password, the installer offers to reuse the same password for LUKS, or you can set a separate LUKS password. A separate one is more secure (your encryption key is not tied to your login), but you then have two passwords to remember.

Note

This password is the key to everything on the disk. It is separate from your login password and there is no recovery — if you lose it, your data is permanently unrecoverable. Use something long, unique, and that you will not forget.

Iteration time

This is how long the key derivation takes on boot:

Value	Trade-off
1000 ms	Fastest boot, least secure
5000 ms	Balanced (default)
60000 ms	Most secure, slowest boot

Higher values make brute-forcing the password harder, at the cost of a slower boot. The stored value is used as iter_time for archinstall and shown in the final summary.

Note

The iteration time is how many times LUKS stretches your password into the actual decryption key. More iterations mean an attacker must spend much more time guessing each password, while you only pay the cost once at every boot. 5000 ms is a good balance for most machines; use higher values if your data is especially sensitive.

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Related

• Disk & Storage — disks, SMART, mounting after install
• Arch Wiki: Data-at-rest encryption

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