In a magnetic-only configuration HPE advises the use of a Battery Backed I/O (BBIO) Storage Controller that has Write Caching enabled in each physical host that is part of the StoreVirtual VSA storage cluster. This is to ensure that write acknowledgements happen in a timely fashion and so write performance stays optimal.
HPE strongly advises to disable the write caching on physical HDDs to avoid data loss.
HPE, VSA [SDS]/12.7, x86
Persistent Write Buffer, Reads/Writes, Data Availability