Synology Inc. HAS5300-12T 12TB 7200 RPM 256MB SAS 12Gb/s 3.5" internal hard drive

Enterprise SAS Drive for Synology NAS

The Synology HAS5300-12T is a 12TB enterprise-grade hard drive built for Synology NAS systems. Its SAS 12Gb/s interface and 7200 RPM spindle speed target environments that demand consistent throughput and tight firmware integration. The 3.5-inch form factor fits standard drive bays in rackmount and tower chassis. Buyers needing non-SAS interfaces or non-Synology firmware optimisation should look elsewhere.

12TB Capacity with 256MB Cache Headroom

The drive provides 12TB of raw storage and a 256MB cache to absorb burst workloads and metadata operations. Sustained sequential transfers reach up to 281 MB/s, so large-volume backups and media ingest stay fast until the mechanical media limit is reached. Random I/O latency and rebuild times will become the bottleneck before the cache saturates. Workloads requiring significantly higher IOPS or sub-millisecond latency exceed what this spinning-media design can deliver.

SAS 12Gb/s Interface Practical Limits

The SAS 12Gb/s link offers ample bandwidth for the drive’s 281 MB/s sustained rate, leaving headroom for command overhead and multi-drive arrays. Firmware updates apply with one click through DSM, and the drive is rated for 2.5 million hours MTTF after 200,000 hours of Synology validation testing. Repair of degraded RAID arrays runs up to 27% faster than similar-class drives on the same platform. Systems without SAS backplanes or DSM management cannot use this drive.