A drive caddy, also sold as a carrier, sled or tray, is the frame that holds a disk in a hot-swap bay. It lines the drive's connector up with the backplane, locks it in with a latch or lever and, on most server designs, carries the activity and fault lights through to the front bezel. Server caddies are specific to the vendor and usually to the generation, so the useful starting point is the chassis rather than the drive. Everything in this category is an internal server carrier. If you are looking for a USB enclosure to turn a laptop drive into a portable disk, that is a different product altogether.
At a glance
- Formats
- SFF carriers for 2.5in hard drives and SSDs, and LFF carriers for 3.5in drives. All are hot-swap designs for front-loading server bays.
- Dell PowerEdge rack
- 11th to 13th generation: the 08FKXC 2.5in carrier and the X968D 3.5in caddy, also listed as 0X968D. 14th generation: the DXD9H for SFF bays and the X7K8W for LFF bays.
- Dell PowerEdge blades
- The NRX7Y SFF blade caddy for the M420, M520, M620, M630 and M640.
- HPE ProLiant
- Standard Gen8, Gen9 and Gen10 carriers: 651687-001 for SFF bays and 651314-001 for 3.5in LFF bays. HPE calls this design the SmartDrive carrier, which is why buyers often search for it as an HP smart caddy.
- Cisco UCS
- The 800-35052-01 SFF caddy for UCS C220, C240 and C460 M3 and M4 rack servers.
- Supermicro
- The SC93301 Supermicro LFF drive tray and the toolless Gen 3 2.5in carrier 01-CSR1722-XX00C102, listed for CSE-826 and related chassis.
- Interface
- The caddy itself is passive. Whether a bay runs SAS, SATA or NVMe is decided by the backplane and storage controller, so check those before choosing drives.
- Hot-swap
- A correctly fitted caddy lets you pull and replace a drive with the server running, provided the controller and RAID level support it.
Matching a caddy to your server
The drive is a standard part; the carrier is not. Three checks settle almost every order.
Vendor and generation
Dell changed its carrier design at the 14th generation, so a caddy from an R630 or R730 will not latch in an R640 or R740, and the reverse holds too. HPE kept one standard carrier across ProLiant Gen8, Gen9 and Gen10, which keeps spares simple within that span. For anything older than Gen8, check the part number on an existing tray before ordering.
Bay size
SFF 2.5in bays are narrower and usually more numerous across the front of the chassis; LFF 3.5in bays are taller, with fewer per server. A 2.5in drive will physically sit in some 3.5in carriers, but that is not the same as working in the bay, as the FAQs below explain.
Part number
The quickest route is the label on an existing caddy. Dell part codes are often printed with a leading zero, so 0X968D and X968D refer to the same part. HPE spare numbers for bare carriers end in -001, while -B21 numbers generally describe a complete option kit rather than an empty tray, so compare like with like.
Typical deployments
Adding capacity to a part-populated server
Refurbished servers often arrive with blanking panels in the unused bays. Blanks keep airflow right but have no drive mount, so every new disk needs a caddy. Plan the array before ordering: RAID 5, 6 and 10 sets want identical drives, and some chassis only wire a subset of bays to the controller, so confirm how many are live first.
Moving boot or data volumes to SSD
A 2.5in SATA or SAS SSD shares the footprint of an SFF hard drive, so it drops straight into a standard 2.5 caddy. For a boot mirror, two modest SSDs are plenty. For databases and VM datastores, prioritise endurance and consistent write latency over headline capacity, and leave bulk files on spinning disks.
2.5in drives in a 3.5in chassis
A common situation with LFF servers bought for raw capacity that later need a few SSDs. Some LFF carriers have mounting holes for a 2.5in drive, but the connector then sits in the wrong place for the backplane. You need a carrier or adapter built to move the connector into the 3.5in position. If the box will end up mostly flash, an SFF chassis is the better long-term choice.
Replacing damaged or missing carriers
Snapped release levers, cracked bezels and trays lost during a move are the usual reasons for buying a single caddy. Match the generation exactly. A carrier from the wrong family may slide part way in, but it will not latch or seat the drive against the backplane.
Spares for a server estate
Replacement drives often turn up bare or in the wrong carrier. Keeping a couple of matched caddies per server model on the shelf, ideally with a spare drive already fitted, turns a failed disk into a quick swap while the RAID rebuild runs in the background. Standardising on one generation per site reduces the number of part numbers you need to hold.
Blades and 1U compute
Density narrows the choice. PowerEdge M-series blades use their own SFF caddy rather than the rack carrier. On the Cisco side, the 1U UCS C220 M3 and M4 take the same SFF carrier as the 2U C240, which simplifies spares across a mixed UCS estate. Supermicro carriers follow the chassis family rather than a server generation.
Why buy from Compuwyze
- Caddies for Dell, HPE, Cisco and Supermicro servers alongside the drives to go in them, so the bay and the disk arrive in one order
- 12-month return-to-base warranty on caddies and other simple items
- Orders for simple items placed before 2pm are aimed to ship the same day
- Free UK delivery on orders over £50, normally next working day once shipped
- International shipping by FedEx economy or priority, usually 2 to 5 days
- 30-day returns, with return shipping paid by the customer
Server caddy FAQs
Will a 2.5 caddy from one server generation fit another?
Only within the span the part was designed for. Dell 11th to 13th generation PowerEdge rack servers share the 08FKXC SFF carrier, while the 14th generation uses the DXD9H, and the two are not interchangeable. HPE's 651687-001 covers ProLiant Gen8 to Gen10. If your server falls outside the range named in a product title, ask us before ordering.
Can I fit an SSD in a server hard drive caddy?
Yes, if it is a 2.5in SATA or SAS SSD going into an SFF carrier; it mounts exactly like a 2.5in hard drive. NVMe U.2 drives share the 2.5in size but need a bay wired for NVMe, and fitting one in a caddy will not change what the backplane supports.
Will a 2.5in drive work in a 3.5in caddy?
Not on its own. Many LFF carriers have screw holes for a 2.5in drive, but the drive's connector ends up short of the backplane. You need a carrier or adapter designed to bring a 2.5in drive's connector to the 3.5in position for that specific server.
Do I need a caddy in every empty bay?
No. Leave the blanking panels in bays with no drive, as they keep air flowing over the installed drives and controller as the manufacturer intended. Buy caddies only for the bays you are populating.
Does the Cisco 800-35052-01 caddy fit a UCS C220 M5?
The listing covers the UCS C220, C240 and C460 in M3 and M4 generations. For a C220 M5, check the part number on one of your existing carriers or get in touch rather than assuming compatibility.
What should I look for in a refurbished caddy?
Most carriers are passive mechanical parts, so condition comes down to the latch, release lever, rails and light pipe. Buying by the manufacturer's part number matters more than price: a carrier made to the original tolerances seats the drive firmly, which counts in a fully loaded chassis where one poorly seated disk can drop out of an array.