Filesystems
Alpine Linux supports a number of filesystems.
Filesystem Tools
Alpine has multiple storage media formatting packages available. Different packages/programs are used to format different types of filesystems.
| Tool | Filesystem | Brief Notes |
|---|---|---|
| btrfs-progs | Btrfs | |
| dosfstools | FAT12/FAT16/FAT32 | |
| e2fsprogs | ext2/ext3/ext4 | ext4 is current default |
| f2fs-tools | F2FS | |
| hfsprogs | XFS HFS/HFS+ | Apple/Mac products |
| jfsutils | JFS | |
| ntfs-3g | NTFS | Microsoft/Windows FUSE driver |
| xfsprogs | XFS |
Swap Partition
Swap space is used for two purposes
- Extend the virtual memory beyond the installed physical memory (RAM) to avoid Out of memory condition
- 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.
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. Ensure that source device name is correct. :
Contents of /etc/conf.d/dmcrypt
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