Storage decides how fast a server feels more often than the CPU does. NVMe, SATA SSDs and hard disks differ by a factor of a thousand in some tasks, and by a factor of ten in price per terabyte. Here is how to pick.
The three types at a glance
| NVMe SSD | SATA SSD | HDD | |
|---|---|---|---|
| Sequential speed | Several GB/s (PCIe 4.0 up to about 7 GB/s) | About 550 MB/s (SATA limit) | About 150–280 MB/s |
| Random access (IOPS) | Hundreds of thousands | Tens of thousands | About 100–200 |
| Price per TB | Highest | Medium | Lowest |
| Sizes | Up to several TB per drive | Up to several TB per drive | Over 20 TB per drive |
Typical values for current drives; single models can be faster or slower.
When NVMe is worth it
Databases, virtual machines, game servers and busy websites read and write many small blocks at random places. That is where hard disks are slowest and NVMe is fastest. For these jobs NVMe is the default, and the difference is something users notice. Our Ryzen servers in Vienna and Berlin come with NVMe, from 2× 1 TB up to 2× 8 TB.
When hard disks are the better choice
Backups, archives, media libraries and log storage are written once and read in long sequential runs. Hard disks handle that well and cost far less per terabyte, so many terabytes stay affordable. Our storage servers start at 8 TB and go up to several hundred terabytes.
Combine them
A common setup is NVMe for the operating system, databases and hot data, plus large hard disks for everything that is big and rarely touched. You get speed where it matters and capacity where it is cheap.
RAID with large disks
Mirror important data (RAID 1 or RAID 10). With very large hard disks, a rebuild after a failure can take a day or longer, and a second failure in that time loses data in RAID 5. For big disks, RAID 6 or RAID 10 is the safer choice. RAID does not replace a backup: deleted or encrypted files are gone on every disk at once.