Does a replacement NAS drive have to be the same brand?

Mixing drive brands in a NAS is fine and common. RAID and SHR care about capacity and recording technology, not the manufacturer: a WD Red Plus can sit next to a Seagate IronWolf without issue.

What actually has to match

• Recording tech: use a CMR drive. An SMR replacement can slow or stall a RAID rebuild.
• Capacity: the replacement must be at least as large as the drive it replaces (larger is fine).
• Class: a NAS-rated drive (IronWolf, WD Red Plus/Pro, Toshiba N300) or an enterprise drive (Exos, Ultrastar), built for 24/7 operation, with vibration tolerance and appropriate workload ratings.

The one brand caveat: 2025 Synology

Synology's 2025 DiskStation Plus models briefly restricted storage-pool creation to Synology-listed drives. DSM 7.3 (October 2025) reversed that for unlisted hard drives and 2.5-inch SATA SSDs, so third-party CMR drives install and pool normally again on those models. M.2 NVMe still requires a Synology-listed drive there (unlisted NVMe shows as "Unverified"). Note the carve-out: RackStation Plus and enterprise-series models still require listed HDDs for new storage pools (unlisted HDDs migrate only). Check your model's current status against Synology's compatibility documentation before buying.

Practical advice

Buying a different brand than your existing drives is not a problem and can be smart: it avoids a whole array of drives from the same manufacturing batch aging identically. Pick the best CMR NAS drive by price per terabyte; the table shows what is in stock.