Did you see the last "Veeam Community Forums Digest" newsletter?
Huge news for all ReFS users! Together with many of you, we've spent countless hours discussing that strange ReFS support policy update from last year, which essentially limited ReFS to Storage Spaces and standalone disks only. So no RAID controllers, no FC or iSCSI LUNs, no nothing – just plain vanilla disks, period. As you know, I've been keeping in touch with Microsoft ReFS team on this issue all the time, translating the official WHYs they were giving me and being devil's advocate, so to speak (true MVP eh). Secretly though, I was not giving up and kept the firm push on them – just because this limitation did not make any sense to me. Still, I can never take all the credit because I know I'd still be banging my head against the wall today if one awesome guy - Andrew Hansen - did not join that Microsoft team as the new PM. He took the issue very seriously and worked diligently to get to the bottom of this, eventually clearing up what in the end appeared to be one big internal confusion that started from a single bad documentation edit.
Bottom line: ReFS is in fact fully supported on ANY storage hardware that is listed on Microsoft HCL. This includes general purpose servers with certified RAID controllers, such as Cisco S3260 (see statement under Basic Disks), as well as FC and iSCSI LUNs on SAN such as HPE Nimble (under Backup Target). What about those flush concerns we've talked about so much? These concerns are in fact 100% valid, but guess what – apparently, Microsoft storage certification process has always included the dedicated flush test tool designed to ensure this command is respected by the RAID controller, with data being protected in all scenarios – including from power loss during write – using technologies like battery-backed write cache (for example, S3260 uses supercapacitor for this purpose). Anyway - I'm super excited to see this resolved, as this was obviously a huge roadblock to ReFS proliferation.