Storage types

The Storage Scale solution offers three different storage types: scratch, persistent, and evaluation.

Scratch storage

A scratch configuration uses virtual server instances with instance storage. If a virtual server instance with instance storage is powered off, all data stored on the instance storage volumes is rendered inaccessible after a subsequent power up of the virtual server instance. Therefore, use of scratch storage is not recommended for long running or mission-critical workloads.

Persistent storage

A persistent configuration uses bare metal servers with locally attached NVMe storage. In addition to higher resilience, persistent storage provides higher performance and capacity than scratch storage.

Evaluation storage

Evaluation storage is based on Storage Scale Developer Edition. This option supports all advanced features of Storage Scale Data Management Edition but is limited to 12TB of storage.

With evaluation storage, you can try out the Storage Scale solution on IBM Cloud® without a license. The automated deployment is done on virtual server instances with instance storage, with Storage Scale Developer Edition packages, and is available only for prototyping and testing purposes.

Storage type comparison

Table 1. Spectrum Scale storage types comparison
The first row of the table describes a Spectrum Scale feature, and the first column describes the specifics of that feature as it pertains to scratch storage. The second column describes the specifics of persistent storage, and the third column describes the specifics of evaluation storage, which map to the Spectrum Scale feature in each row.
	Scratch (default)	Persistent	Evaluation
Storage cluster nodes	Virtual server instances	Bare metal servers	Virtual server instances
Compute cluster nodes	Virtual server instances	Virtual server instances	Virtual server instances
Storage cluster node count	Min 3 Max 18	Min 3 Max 10	Min 3 Max 18
Compute cluster node count	Min 3 Max 64	Min 3 Max 64	Min 3 Max 64
Storage cluster OS support	RHEL 8.6 (custom or stock images)	RHEL 8.6 (stock image)	RHEL 8.6 (custom image)
Compute cluster OS support	RHEL 7.9, 8.6 (custom or stock images)	RHEL 7.9, 8.6 (custom or stock images)	RHEL 7.9, 8.6 (custom or stock images)
Spectrum Scale edition and version	Spectrum Scale Data Management Edition v5.1.8.1	Spectrum Scale Data Management Edition v5.1.8.1	Spectrum Scale Developer Edition v5.1.8.0
IBM Customer Number required?	Yes	Yes	No
Customer support available?	Yes	Yes	No

For more information about Storage Scale editions, see IBM Storage Scale product editions.