Talos Linux has a set of system volumes that are used for various purposes, such as storing the system state, ephemeral data, and more. This guide provides an overview of the system volumes and how to configure them.

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EPHEMERAL Volume

The EPHEMERAL volume is a system volume that is used for storing ephemeral data, such as container data, downloaded images, logs, and etcd data (for controlplane nodes).
Note: The volume configuration in the machine configuration is only applied when the volume has not been provisioned yet. So applying changes after the initial provisioning will not have any effect.
To configure the EPHEMERAL (/var) volume, append the following document to the machine configuration: 
apiVersion: v1alpha1
kind: VolumeConfig
name: EPHEMERAL
provisioning:
  diskSelector:
    match: disk.transport == 'nvme'
  minSize: 2GB
  maxSize: 40GB
  grow: false
Every field in the VolumeConfig resource is optional, and if a field is not specified, the default value is used. The default built-in values are: 
provisioning:
    diskSelector:
        match: system_disk
    minSize: 2GiB
    grow: true
By default, the EPHEMERAL volume is provisioned on the system disk, which is the disk where Talos Linux is installed. It has a minimum size of 2 GiB and automatically grows to utilize the maximum available space on the disk. If you would like to keep the EPHEMERAL volume on the system disk but limit its size to 40 GiB, you can set the maxSize field to 40GiB: 
apiVersion: v1alpha1
kind: VolumeConfig
name: EPHEMERAL
provisioning:
  maxSize: 40GiB
If you want to create a separate partition for EPHEMERAL on a different disk, you can set the diskSelector field to select the desired disk: 
apiVersion: v1alpha1
kind: VolumeConfig
name: EPHEMERAL
provisioning:
  diskSelector:
    match: disk.transport == 'nvme' && !system_disk

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IMAGECACHE Volume

This system volume is not provisioned by default, and it only gets created if the Image Cache feature is enabled. See Image Cache configuration for more details.