Volumes

Volumes

Volumes are block devices. They comprise one or more Media Nodes serving a specific Application Node provisioned by Volumez.

• You control all the parameters of your Volumes (such as size).

• To control resiliency, you can create ephemeral logical volumes, single-zone volumes with predefined degrees of failure tolerance, and multi-zone volumes:

  • Ephemeral – No mirroring: there is one copy of the data on a single Media Node.

  • Node Mirroring – High Availability within a single Availability Zone. Data is duplicated on other Media Nodes and can survive one or more media node failures.

  • Cross Zones Mirroring – Data is duplicated across more than one Availability Zone. Data can survive a Media Node or an Availability Zone failure.

• You select the Application Node to which the volume will be attached.

The State of the Volume:

• Creating - The volume create call is waiting to be scheduled.

• Preparing - The volume creation process is ongoing, and has not reached completion yet.

• Online - The volume is ready to serve the application’s requirements.

• Offline - The data is inaccessible.

• Updating - The volume resize is being initiated for more physical capacity on the disk.

• Degraded - The volume is experiencing partial resiliency and/or partial performance. The specified resiliency and performance are not being achieved.

  • New data can be written to the volume.

  • Snapshots cannot be created.

  • Volume Resize cannot take place.

  • The degraded state can be recovered automatically, or manually by clicking on Volumes → Recover.

• Recovery -

  • Automatically initiated recovery - This takes place while syncing media from offline to online automatically, if a media was temporarily offline.

  • User initiated recovery (replacing medias) - can take place only after media was offline for 40 minutes.

  • While in recovery state:

    • New data can be written to the volume.

    • Snapshots cannot be created.

    • Volume Resize cannot take place.

  • Recovery will take up to 8 hours. Volumez will prioritize completion by utilizing more node resources (up to 20% in total).

• Deleting - After the attachment is deleted, a volume can be deleted by the user.