Every volume(LUN) can be dynamically re-assigned to different performance tiers.
Every volume in StorPool is associated to a "template". The template specifies the replication level, which drive pools (aka placement groups) and default IOPS and MB/s limits. Multiple templates can be configured in a StorPool storage system. For example one template could be created for a NVMe storage pool, another template could be for a SSD-HDD hybrid pool (with 1-2 copies on SSDs and 1-2 copies on HDDs) and yet another template could be for HDD-only storage.
A volume can be moved between templates online, without interrupting the storage service. In most cases a volume (LUN) in StorPool corresponds to one virtual disk of a VM or one persistent volume of a container/pod.
Drive pools (placement groups) can be changed online, without interrupting the service, for example to add or remove storage nodes and individual drives (SSDs, HDDs) from them. Templates can also be changed to refer to different drive pools. For example if the user decides that a large group of volumes needs to be moved to different media.