RAIDZ is part of the VDEV (Virtual Device) layer. Layered on top of this is the ZIO (ZFS I/O layer). Together, these form the SPA (Storage Pool Allocator).
On top of this layer we have the ARC, L2ARC and ZIL. (Adaptive Replacement Caches and ZFS Intent Log).
Then on top of this layer we have the DMU (Data Management Unit), and then on top of that we have the DSL (Dataset and Snapshot Layer). Together, the SPA and DSL layers implement the Meta-Object Set layer, which in turn provides the Object Set layer. These implement the primitives for building a filesystem and the various file types it can store (directories, files, symlinks, devices etc.) along with the ZPL and ZAP layers (ZFS POSIX Layer and ZFS Attribute Processor), which hook into the VFS.
ZFS isn't just a filesystem. It contains as many, if not more, levels of layering than any RAID and volume management setup composed of separate parts like mdraid+LVM or similar, but much better integrated with each other.
It can also store stuff that isn't a filesystem. ZVOLs are fixed size storage presented as block devices. You could potentially write additional storage facilities yourself as extensions, e.g. an object storage layer.
It doesn't.
RAIDZ is part of the VDEV (Virtual Device) layer. Layered on top of this is the ZIO (ZFS I/O layer). Together, these form the SPA (Storage Pool Allocator).
On top of this layer we have the ARC, L2ARC and ZIL. (Adaptive Replacement Caches and ZFS Intent Log).
Then on top of this layer we have the DMU (Data Management Unit), and then on top of that we have the DSL (Dataset and Snapshot Layer). Together, the SPA and DSL layers implement the Meta-Object Set layer, which in turn provides the Object Set layer. These implement the primitives for building a filesystem and the various file types it can store (directories, files, symlinks, devices etc.) along with the ZPL and ZAP layers (ZFS POSIX Layer and ZFS Attribute Processor), which hook into the VFS.
ZFS isn't just a filesystem. It contains as many, if not more, levels of layering than any RAID and volume management setup composed of separate parts like mdraid+LVM or similar, but much better integrated with each other.
It can also store stuff that isn't a filesystem. ZVOLs are fixed size storage presented as block devices. You could potentially write additional storage facilities yourself as extensions, e.g. an object storage layer.