Seagate ST3300955FC 300GB FC 15K HDD: Part Numbers Decoded
Search for a 300GB Fibre Channel 15K drive and you will find several part numbers that appear identical on specification. They are not always interchangeable, and understanding why saves an order that arrives and does not work.
The Seagate ST3300955FC is a 300GB Fibre Channel 4Gb 15K 3.5-inch Cheetah drive, identified by Seagate’s own model number.
Manufacturer model numbers and OEM part numbers
The same physical drive can carry two or more identities, and knowing which one you are looking at matters.
A manufacturer model number like ST3300955FC is Seagate’s own designation. It identifies the drive, its capacity, its interface and its firmware family as Seagate built it.
An OEM part number is what a storage vendor assigns when they qualify that drive for their platform, often with vendor firmware applied. Seagate part numbers in the 9Nxxxx format frequently indicate a build to an OEM specification.
Where the array is a generic Fibre Channel shelf that accepts standard Seagate firmware, either identity works and the model number is the cleaner reference. Where the array is a vendor system that validates firmware, you need the vendor’s part — NetApp being the extreme case, since its disks are formatted with non-standard sector sizes and reject standard drives outright.
So the first question on any FC order is not "what are the specifications" but "what does the shelf expect".
ST3300955FC specifications
| Part Number | ST3300955FC |
| Manufacturer | Seagate |
| Product Family | Cheetah |
| Capacity | 300GB |
| Interface | Fibre Channel 4Gb |
| Rotational Speed | 15,000 RPM |
| Form Factor | 3.5 inch LFF |
| Drive Class | Enterprise Performance |
| Condition | Refurbished, function-tested |
| Warranty | 30-day TechSellerUSA warranty |
Reading a Seagate model number
Seagate model numbers are systematic, and learning the pattern is genuinely useful when scanning search results.
ST is the Seagate prefix on every drive.
3 indicates the 3.5-inch form factor. A 2.5-inch drive would show a different digit here.
300 is the capacity in gigabytes.
955 covers the generation and cache configuration.
FC is the interface: Fibre Channel. You will see NS and MM and other codes on SAS drives, AS and similar on SATA.
That last pair of characters is the fastest way to rule a drive in or out. If you need Fibre Channel and the model ends in anything else, it will not work — there is no adapter between FC and SAS, and the connectors are physically different.
SKU: ST3300955FC  | Refurbished & function-tested  | 30-day warranty
View Details & Request a Quote →Fibre Channel loop topology and why drives are shelf-specific
Fibre Channel disk shelves use an arbitrated loop rather than the point-to-point connections SAS uses. Every drive on the loop shares bandwidth and each has a loop identifier, usually determined by its physical bay position.
Two practical consequences follow.
Bay position matters. Because loop IDs are typically derived from slot position, moving drives between bays can change how the shelf sees them. Replace in place rather than rearranging.
A faulty drive can affect the loop. On a shared loop, a drive misbehaving electrically can disrupt communication for others on the same loop — a failure mode that does not exist on point-to-point SAS. It is one reason FC shelves sometimes present confusing symptoms where multiple drives appear troubled at once.
If you are seeing odd behaviour across several drives in an FC shelf, that is worth knowing before you conclude you have multiple failures.
A finite and shrinking supply
Fibre Channel drives have not been manufactured for years. Every unit still available came out of a system somewhere, and the population only decreases.
For anyone maintaining FC storage, two things follow. Count your exposure — how many drives of each part number are in service against how many spares you hold. And set a migration horizon deliberately, because parts availability places a practical end date on the platform whether or not you plan for it.
Planning a migration while spares are obtainable leaves you with options. Being forced into one by a failure you cannot source leaves you with an outage. Our 9N7007-024 guide covers the same platform from the OEM part angle.
Ordering
We supply the ST3300955FC refurbished and function-tested with a 30-day warranty. Send us your shelf model and we will confirm whether it accepts standard Seagate firmware or requires a vendor-coded part before you order. Browse the full Seagate range or our complete enterprise hard drives catalogue.
Common questions
What is the difference between ST and 9N Seagate part numbers?
ST numbers are Seagate’s own model designations. Numbers in the 9N format frequently indicate a build to an OEM specification, often with vendor firmware applied. Which you need depends on whether your shelf validates firmware.
How do I read a Seagate model number?
ST is the prefix, the next digit gives form factor, then capacity in gigabytes, then generation and cache configuration, then interface code. FC indicates Fibre Channel; other codes indicate SAS or SATA. The interface characters are the fastest way to rule a drive in or out.
Can I move FC drives between bays in a shelf?
Better not to. Fibre Channel uses an arbitrated loop where loop identifiers are typically derived from physical slot position, so moving drives can change how the shelf sees them. Replace in place rather than rearranging.
Why do several drives sometimes look faulty at once in an FC shelf?
On a shared arbitrated loop, one drive misbehaving electrically can disrupt communication for others on the same loop. That failure mode does not exist on point-to-point SAS, and it is worth ruling out before concluding you have multiple failures.
Send us your shelf model and we will confirm firmware requirements before quoting.
