Persistent volume instances function like standard volume instances, except they retain their contents when their edge app or node shuts down. Data on a persistent volume instance will remain even if its associated app is deleted.
An important distinction between standard and persistent volume instances in the ZEDEDA Cloud system is which entity owns the volume instance. Standard volume instances belong to an edge app instance. Persistent volume instances, however, belong to an edge node, which allows them to have their own life cycle.
Because each persistent volume instance belongs to an edge node, if you want a particular persistent volume instance to run on multiple edge nodes, you need to create that volume instance on each of those edge nodes.
You can automate creation of volume instances using the ZEDEDA API, the ZEDEDA Terraform Provider, or the ZEDEDA CLI. Or, you can set up a deployment project definition, enabling auto-creation of your volume instance.
Creating a persistent volume instance
You create persistent volume instances the same way as standard volume instances. See our guide to volume instances.
Add a persistent volume to an edge app
You can add a persistent volume instance to an edge app in the same way as standard volume instances with one significant difference. When you create your edge app, in the Drives section, whether you check the Purge button or not determines if your volume instance will be perishable or persistent. To make your volume instance persistent, leave the Purge option unchecked.
Note that because you must leave the Purge option unchecked, the Purge and Update process will not be available for your persistent volume.
For instructions about how to add a volume instance to an edge app, see our guides to edge apps.