Configuring Volumes Options

Owned by Rumena Zlatkova (Deactivated)
Last updated: Dec 12, 2023 by Bala Harish A(AC)
2 min read

The disk.volumes option in the node or cluster configuration file specifies the volumes used by Swarm. This specification includes the device names and optional flags for handling these volumes. One disk.volumes definition is allowed in a configuration file. This setting cannot be changed dynamically (in the Swarm UI or SNMP).

Warning

Swarm erases any non-Swarm data on all volumes it uses. For best results, run Swarm only on nodes that are free of non-Swarm data.

disk.volumes Setting

Best Practice

Use disk.volumes = all, which enables Swarm to use all volumes greater than the configured disk.minGB (64 GB by default).

Configure Swarm to format and mount smaller disks by decreasing the value of disk.minGB. A USB flash drive is automatically excluded from the volume list if booting Swarm from one.

Additionally, disk.volumes = all:

  • Supports hot plugging

  • Supports exceptions (all except)

  • Supports:k (keep policy) 

Volumes Syntax

disk.volumes = volume-specification  volume-specification ::== all-volumes | volume-list | ''  all-volumes ::== 'all' [ ':' policy ] [ space 'except' space device-list ]  device-list ::== device [ space device [ ... ] ]  device ::== Linux-device-path  space ::== space or Tab character and not the word space  policy ::== 'k'

Example disk.volumes Entries

disk.volumes = all  disk.volumes = all:k  disk.volumes = all except /dev/hda  disk.volumes = /dev/sda /dev/sdb  disk.volumes = /dev/hda:k /dev/hdc:k disk.volumes =

No Volumes: If disk.volumes is set to an empty string, a diskless machine is specified, so Swarm does not mount any volumes. If the disk.volumes setting itself is absent, Swarm mounts all available volumes (equivalent to disk.volumes=all).

Device Option

The device component is either the keyword all or the Linux device path string for the disk. When using the keyword all, do not include any other device path specifications unless they follow except.

Best Practice

Use disk.volumes = all and avoid Linux device paths.

Exclude specific volumes from being formatted and used by Swarm by listing them after except:

disk.volumes = all except /dev/sda dev/sdb

Example Linux Device Paths

  • /dev/hda

  • /dev/sda

  • /dev/sdb

Older IDE disks, also known as Parallel ATA, EIDE, ATA-33, ATA-66, ATA-100, or ATA-133, use hd device names. These disks are configured as master or slave devices on each IDE controller. Typically, the master devices are /dev/hda and /dev/hdc, while the slave devices are /dev/hdb and /dev/hdd.

SCSI, SAS, and SATA disks typically use sd device names. The device letters are assigned sequentially in the order in which the disks are discovered starting at /dev/sda. The hardware report in the utility menu shows the actual names in use on a node.

If an invalid device name is specified in the device component, the node log indicates an error during the format operation. Incorrectly-specified volumes are not used.

Policy Option

The policy option allows instructing Swarm how to handle a volume. Currently, these handling features involve the formatting characteristics of the physical device.

The format policy allows overriding the default volume expiration behavior by specifying the :k (keep) policy.

See Returning a Stale Volume to Service.



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