What's the practical difference between Primary Storage and Secondary Storage in CloudStack?

CloudStack
1

The easiest way to remember it is:

Primary Storage = running VM data

Secondary Storage = deployment/source data

Primary Storage is used for VM volumes and the storage associated with running workloads.

Secondary Storage is used for things such as:

  • Templates

  • ISOs

  • Snapshots

So when troubleshooting storage, first identify what operation is failing.

For example:



VM disk problem       → Primary Storage
Template unavailable  → Secondary Storage
ISO unavailable       → Secondary Storage

That distinction helps narrow the investigation quickly.