Seagate ST1200MM0198 1.2TB SAS 10K HDD: Specs and RAID Planning
If there is one drive specification that quietly became the industry default for mixed server workloads, it is 1.2TB at 10K on SAS. It sits at the point where capacity stops being the constraint and performance is still comfortable, and it is why this part number shows up in so many server configurations.
The Seagate ST1200MM0198 is a 1.2TB SAS 12Gb/s 10K 2.5-inch enterprise performance drive.
How the 10K capacity ceiling moved
Enterprise 10K drives spent years capped around 300GB and 600GB, which meant a performance array needed a lot of bays to reach a usable volume size. Populating twenty-four bays with 600GB drives to build a 10TB datastore was normal, and it consumed a whole chassis.
1.2TB doubled that per bay without giving up spindle speed. The consequence was not just cheaper capacity — it changed what a single 2U server could hold. A twenty-four-bay chassis filled with 1.2TB drives reaches capacities that previously needed an external enclosure.
That is why 1.2TB became the volume seller in this class. It is not the fastest drive, and it is not the cheapest per terabyte. It is the one that removes the most design constraints at once.
ST1200MM0198 specifications
| Part Number | ST1200MM0198 |
| Manufacturer | Seagate |
| Capacity | 1.2TB |
| Interface | SAS 12Gb/s |
| Rotational Speed | 10,000 RPM |
| Form Factor | 2.5 inch SFF |
| Drive Class | Enterprise Performance |
| Condition | Refurbished, function-tested |
| Warranty | 30-day TechSellerUSA warranty |
Where 1.2TB at 10K belongs
Virtualisation datastores are the obvious case. A VM host runs a mixture of busy and idle guests, and the storage needs to handle concurrent random I/O from all of them without the capacity forcing you into more bays than the chassis has.
Mid-sized databases sit in the same space. Not the latency-critical transactional core that justifies flash, but the reporting instance, the development copy, the departmental system where good-enough response times at reasonable cost is the actual requirement.
Active file shares and application servers round it out. Data that is genuinely accessed rather than archived, at volumes too large for a tray of 600GB drives to hold comfortably.
Where it is the wrong answer: pure archive and backup, where nearline drives cost a fraction per terabyte, and the most latency-sensitive transactional work, where 15K spindles or flash are the right tier.
SKU: ST1200MM0198 | Refurbished & function-tested | 30-day warranty
View Details & Request a Quote →Planning capacity around RAID overhead
A point that catches people when sizing an array from raw drive capacity.
Twenty-four 1.2TB drives is 28.8TB raw. What you actually get depends entirely on the RAID level and the spare allocation, and the difference is not small.
RAID 10 mirrors everything, so usable capacity is roughly half the raw total. That is expensive in capacity terms and it is frequently the right choice for virtualisation, because rebuild is a straight copy from the surviving mirror rather than a parity reconstruction reading every drive.
RAID 6 gives up two drives to parity, so usable capacity is much higher. Rebuilds read every remaining drive and take longer, but the array survives a second failure during that window.
Hot spares come off the top before any of this. A twenty-four-bay array with two hot spares has twenty-two drives to work with.
Deciding this before you order avoids the common outcome of buying exactly enough drives to hit a raw number and then discovering the usable volume is far smaller than the project needed.
Bare drive, no OEM carrier
This is the manufacturer part with no server carrier and no OEM firmware coding. It suits Supermicro, white-box and generic-tray chassis, and costs less than an OEM-branded drive on the same mechanism.
It is the wrong choice where an HPE Smart Array, Dell PERC or IBM ServeRAID controller expects vendor firmware, or where you need the tray supplied. Our compatibility guide lists the OEM part numbers for each platform.
Ordering
We supply the ST1200MM0198 refurbished and function-tested with a 30-day warranty, single spares or in volume for full-chassis population. Tell us your bay count, RAID level and spare allocation and we will quote the right number of drives rather than the raw total. Browse the full Seagate range or our complete enterprise hard drives catalogue.
Common questions
Why is 1.2TB such a common enterprise capacity?
It doubled the 10K capacity ceiling from the 600GB era without giving up spindle speed, which changed what a single chassis could hold. A twenty-four-bay 2U server filled with 1.2TB drives reaches capacities that previously needed an external enclosure.
How much usable capacity will I actually get?
Considerably less than the raw total. RAID 10 gives roughly half, RAID 6 gives up two drives to parity, and hot spares come off the top before either. Decide the RAID level and spare allocation before ordering rather than after.
RAID 10 or RAID 6 for a virtualisation datastore?
RAID 10 costs half the raw capacity but rebuilds as a straight copy from the surviving mirror rather than a parity reconstruction reading every drive, which is why it is frequently chosen for virtualisation despite the overhead.
Should I use this for backup storage?
No. Backup and archive are capacity problems, and nearline drives cost a fraction per terabyte for sequential workloads. Save 10K drives for data that is genuinely accessed.
Tell us bay count, RAID level and spare allocation and we will quote the actual drive count you need.
