swapDevices

Swapdevices

`swapDevices`

The swap devices and swap files. These must have been initialised using {command}mkswap. Each element should be an attribute set specifying either the path of the swap device or file (device) or the label of the swap device (label, see {command}mkswap -L). Using a label is recommended.

Type: list of (submodule)

Default

[ ]

Example

[{device = "/dev/hda7";}{device = "/var/swapfile";}{label = "bigswap";}]

Declared by: https://github.com/nixos/nixpkgs/blob/master/nixos/modules/tasks/encrypted-devices.nix

`swapDevices.*.device`

Path of the device or swap file. Type: non-empty string

Example

"/dev/sda3"

Declared by: https://github.com/nixos/nixpkgs/blob/master/nixos/modules/config/swap.nix

`swapDevices.*.discardPolicy`

Specify the discard policy for the swap device. If "once", then the whole swap space is discarded at swapon invocation. If "pages", asynchronous discard on freed pages is performed, before returning to the available pages pool. With "both", both policies are activated. See swapon(8) for more information.

Type: null or one of "once", "pages", "both"

Default

null

Example

"once"

Declared by: https://github.com/nixos/nixpkgs/blob/master/nixos/modules/config/swap.nix

`swapDevices.*.encrypted.blkDev`

Location of the backing encrypted device. Type: null or string

Default

null

Example

"/dev/sda1"

Declared by: https://github.com/nixos/nixpkgs/blob/master/nixos/modules/tasks/encrypted-devices.nix

`swapDevices.*.encrypted.enable`

The block device is backed by an encrypted one, adds this device as a initrd luks entry. Type: boolean

Default

false

Declared by: https://github.com/nixos/nixpkgs/blob/master/nixos/modules/tasks/encrypted-devices.nix

`swapDevices.*.encrypted.keyFile`

Path to a keyfile used to unlock the backing encrypted device. When systemd stage 1 is not enabled, at the time this keyfile is accessed, the neededForBoot filesystems (see utils.fsNeededForBoot) will have been mounted under /mnt-root, so the keyfile path should usually start with "/mnt-root/". When systemd stage 1 is enabled, fsNeededForBoot file systems will be mounted as needed under /sysroot, and the keyfile will not be accessed until its requisite mounts are done.

Type: null or string

Default

null

Example

"/mnt-root/root/.swapkey"

Declared by: https://github.com/nixos/nixpkgs/blob/master/nixos/modules/tasks/encrypted-devices.nix

`swapDevices.*.encrypted.label`

Label of the unlocked encrypted device. Set fileSystems.<name?>.device to /dev/mapper/<label> to mount the unlocked device. Type: null or string

Default

null

Example

"rootfs"

Declared by: https://github.com/nixos/nixpkgs/blob/master/nixos/modules/tasks/encrypted-devices.nix

`swapDevices.*.label`

Label of the device. Can be used instead of {var}device.

Type: string

Example

"swap"

Declared by: https://github.com/nixos/nixpkgs/blob/master/nixos/modules/config/swap.nix

`swapDevices.*.options`

Options used to mount the swap.

Type: list of non-empty string

Default

["defaults"]

Example

["nofail"]

Declared by: https://github.com/nixos/nixpkgs/blob/master/nixos/modules/config/swap.nix

`swapDevices.*.priority`

Specify the priority of the swap device. Priority is a value between 0 and 32767. Higher numbers indicate higher priority. null lets the kernel choose a priority, which will show up as a negative value.

Type: null or signed integer

Default

null

Example

2048

Declared by: https://github.com/nixos/nixpkgs/blob/master/nixos/modules/config/swap.nix

`swapDevices.*.randomEncryption`

Encrypt swap device with a random key. This way you won't have a persistent swap device.

HINT: run "cryptsetup benchmark" to test cipher performance on your machine.

WARNING: Don't try to hibernate when you have at least one swap partition with this option enabled! We have no way to set the partition into which hibernation image is saved, so if your image ends up on an encrypted one you would lose it!

WARNING #2: Do not use /dev/disk/by-uuid/… or /dev/disk/by-label/… as your swap device when using randomEncryption as the UUIDs and labels will get erased on every boot when the partition is encrypted. Best to use /dev/disk/by-partuuid/…

Type: (submodule) or boolean convertible to it

Default

false

Example

{cipher = "serpent-xts-plain64";enable = true;source = "/dev/random";}

Declared by: https://github.com/nixos/nixpkgs/blob/master/nixos/modules/config/swap.nix

`swapDevices.*.randomEncryption.allowDiscards`

Whether to allow TRIM requests to the underlying device. This option has security implications; please read the LUKS documentation before activating it.

Type: boolean

Default

false

Declared by: https://github.com/nixos/nixpkgs/blob/master/nixos/modules/config/swap.nix

`swapDevices.*.randomEncryption.cipher`

Use specified cipher for randomEncryption.

Hint: Run "cryptsetup benchmark" to see which one is fastest on your machine.

Type: string

Default

"aes-xts-plain64"

Example

"serpent-xts-plain64"

Declared by: https://github.com/nixos/nixpkgs/blob/master/nixos/modules/config/swap.nix

`swapDevices.*.randomEncryption.enable`

Encrypt swap device with a random key. This way you won't have a persistent swap device.

WARNING: Don't try to hibernate when you have at least one swap partition with this option enabled! We have no way to set the partition into which hibernation image is saved, so if your image ends up on an encrypted one you would lose it!

WARNING #2: Do not use /dev/disk/by-uuid/… or /dev/disk/by-label/… as your swap device when using randomEncryption as the UUIDs and labels will get erased on every boot when the partition is encrypted. Best to use /dev/disk/by-partuuid/…

Type: boolean

Default

false

Declared by: https://github.com/nixos/nixpkgs/blob/master/nixos/modules/config/swap.nix

`swapDevices.*.randomEncryption.keySize`

Set the encryption key size for the plain device.

If not specified, the amount of data to read from source will be determined by cryptsetup.

See cryptsetup-open(8) for details.

Type: null or signed integer

Default

null

Example

"512"

Declared by: https://github.com/nixos/nixpkgs/blob/master/nixos/modules/config/swap.nix

`swapDevices.*.randomEncryption.sectorSize`

Set the sector size for the plain encrypted device type.

If not specified, the default sector size is determined from the underlying block device.

See cryptsetup-open(8) for details.

Type: null or signed integer

Default

null

Example

"4096"

Declared by: https://github.com/nixos/nixpkgs/blob/master/nixos/modules/config/swap.nix

`swapDevices.*.randomEncryption.source`

Define the source of randomness to obtain a random key for encryption.

Type: string

Default

"/dev/urandom"

Example

"/dev/random"

Declared by: https://github.com/nixos/nixpkgs/blob/master/nixos/modules/config/swap.nix

`swapDevices.*.size`

If this option is set, ‘device’ is interpreted as the path of a swapfile that will be created automatically with the indicated size (in megabytes).

Type: null or signed integer

Default

null

Example

2048

Declared by: https://github.com/nixos/nixpkgs/blob/master/nixos/modules/config/swap.nix