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	Formatting command	Brief Notes
btrfs-progs	Btrfs	mkfs.btrfs	combines copy-on-write and volume management
dosfstools	FAT12/FAT16/FAT32	mkfs.vfat	also used for EFI partition
e2fsprogs	ext2/ext3/ext4	mkfs.ext4	ext4 is current default in Linux
exfatprogs	exfat	mkfs.exfat	Commonly used on USB flash drives and SD cards
f2fs-tools	F2FS	mkfs.f2fs
hfsprogs	HFS/HFS+	mkfs.hfsplus	Apple/Mac products
jfsutils	JFS	mkfs.jfs
ntfs-3g	NTFS	mkfs.ntfs	Full-featured, Microsoft/Windows FUSE driver
squashfs-tools	SquashFS	mksquashfs	compressed read-only file system
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 defaults 0 0" >> /etc/fstab # rc-update add swap

Instead of device name /dev/sda2, the UUID=device_UUID can also be used in etc/fstab file, if UUID is being used for other partitions.

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 none 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

• Zram
• Manual partitioning
• How to enable encrypted swap in Alpine Linux