Directory - dir#

The directory storage driver is a basic backend that stores its data in a standard file and directory structure. This driver is quick to set up and allows inspecting the files directly on the disk, which can be convenient for testing. However, LXD operations are not optimized for this driver.

dir driver in LXD#

The dir driver in LXD is fully functional and provides the same set of features as other drivers. However, it is much slower than all the other drivers because it must unpack images and do instant copies of instances, snapshots and images.

Unless specified differently during creation (with the source configuration option), the data is stored in the /var/snap/lxd/common/lxd/storage-pools/ (for snap installations) or /var/lib/lxd/storage-pools/ directory.

Quotas#

The dir driver supports storage quotas when running on either ext4 or XFS with project quotas enabled at the file system level.

Configuration options#

The following configuration options are available for storage pools that use the dir driver and for storage volumes in these pools.

Storage pool configuration#

Key

Type

Default

Description

rsync.bwlimit

string

0 (no limit)

The upper limit to be placed on the socket I/O when rsync must be used to transfer storage entities

rsync.compression

bool

true

Whether to use compression while migrating storage pools

source

string

-

Path to an existing directory

Tip

In addition to these configurations, you can also set default values for the storage volume configurations. See Configure default values for storage volumes.

Storage volume configuration#

Key

Type

Condition

Default

Description

security.shifted

bool

custom volume

same as volume.security.shifted or false

Enable ID shifting overlay (allows attach by multiple isolated instances)

security.unmapped

bool

custom volume

same as volume.security.unmapped or false

Disable ID mapping for the volume

size

string

appropriate driver

same as volume.size

Size/quota of the storage volume

snapshots.expiry

string

custom volume

same as volume.snapshots.expiry

Controls when snapshots are to be deleted (expects an expression like 1M 2H 3d 4w 5m 6y)

snapshots.pattern

string

custom volume

same as volume.snapshots.pattern or snap%d

Pongo2 template string that represents the snapshot name (used for scheduled snapshots and unnamed snapshots)

snapshots.schedule

string

custom volume

same as volume.snapshots.schedule

Cron expression (<minute> <hour> <dom> <month> <dow>), or a comma separated list of schedule aliases (@hourly, @daily, @midnight, @weekly, @monthly, @annually, @yearly)