Filesystems

Alpine Linux supports all the popular filesystems for various storage media. Different packages/programs are used to format different types of filesystems.

Filesystem tools

The following table lists the packages related to various filesystems available in Alpine Linux along with the command to format.

Tool	Filesystem	Brief Notes	Formatting command
btrfs-progs	Btrfs		mkfs.btrfs
dosfstools	FAT12/FAT16/FAT32	used for EFI partition	mkfs.vfat
e2fsprogs	ext2/ext3/ext4	ext4 is current default in Linux	mkfs.ext4
exfatprogs	exfat	Commonly used on USB flash drives and SD cards	mkfs.exfat
f2fs-tools	F2FS		mkfs.f2fs
hfsprogs	XFS HFS/HFS+	Apple/Mac products	mkfs.hfsplus
jfsutils	JFS		mkfs.jfs
ntfs-3g	NTFS	Full-featured, Microsoft/Windows FUSE driver	mkfs.ntfs
xfsprogs	XFS		mkfs.xfs

Swap partition

Swap space is used for two purposes

1. Extend the virtual memory beyond the installed physical memory (RAM) to avoid Out of memory condition
2. Suspend-to-disk or Hibernation support

Below Instructions explain how to use a seperate partition for swap:

The following commands prepares the unmounted partition (/dev/sda2) for swap space, activates the prepared swap space and starts the swap service to manage swap space immediately:

# mkswap /dev/sda2
# swapon /dev/sda2 
# rc-service swap start

The command free -m will show how much swap space is available (in MB).

To make the swap persistent across reboots, enable automatic start of swap:

# echo -e "/dev/sda2 none swap sw 0 0" >> /mnt/etc/fstab
# rc-update add swap 

If you prefer maximum speed, you don't need configure any raid devices for swap. Just add 2 swap partitions on different disks and linux will stripe them automatically. The downside is that the moment one disk fails, the system will go down. For better reliability, put swap on RAID1.

Tip: Instead of using a separate partition for swap, zram based swap file can be used.

Encrypted swap

The below steps explains the steps to enable crypt-swap or Encrypted swap parition.

Edit the file /etc/conf.d/dmcrypt to enable crypt-swap and ensure that source device name is correct:

Contents of /etc/conf.d/dmcrypt

swap=crypt-swap source='/dev/nvme0nXXX'

To use dmcrypt, start dmcrypt service and enable swap immediately:

# /etc/init.d/dmcrypt start
# swapon /dev/mapper/crypt-swap

To make the encrypted swap persistent across reboots, enable automatic start of encryption & swap:

# rc-update add dmcrypt
# rc-update add swap

To enable automatic swapon, add the relevant entry to /etc/fstab

# echo /dev/mapper/crypt-swap swap swap defaults 0 0 >> /etc/fstab

Note: The above instructions will reset/re-encrypt swap on every boot and thus no suspend to disk works with it.

See also

• How to enable encrypted swap in Alpine Linux