Q: If I use write-back cache in a Windows Server 2012 R2 Storage Space for a parity space, does it use parity for the write-back cache?
A: When a write-back cache is configured for a Storage Space in Server 2012 R2 which uses SSD disks to provide a very fast initial write target, the resiliency of the Storage Space is matched for the write-back cache.
However, it won't use parity in the write-back cache for performance reasons. If you're using a parity storage space, then the write-back cache will use a two-way mirror.
If you use a dual-parity storage space, then the write-back cache will use a three-way mirror.
Note that the write-back cache is maintaining the same resiliency to the number of possible failed disks without using parity.