Rackmount and Tower Server Chassis

A server chassis is the shell: case, backplane, cooling and often the power supplies, with no processor, memory or drives. Two situations account for most chassis purchases — rebuilding a machine whose case or midplane has failed, and holding a cold spare so a production node can be reconstituted from parts already on the shelf.

Rack units

• 1U — the densest, and the most constrained on cooling and expansion. Low-profile cards only.
• 2U — the volume format. Room for full-height cards and a reasonable drive count.
• 3U and 4U — storage-heavy and GPU builds, where drive bays or card clearance matter more than density.
• Tower — where there is no rack, typically branch office and lab use.

What "CTO" means on a listing

CTO is configure-to-order: the chassis as the factory supplied it before options were fitted. A CTO shell is the right starting point for a rebuild, but read what is included — the backplane, riser cages, fan modules and power supplies are all separately optioned, and a bare CTO chassis may arrive without any of them.

Three things that decide whether a chassis will take your parts

• Backplane — sets the drive count, the form factor and whether the bays are SAS, SATA or NVMe wired. It is the single most consequential part of the chassis.
• Board standoffs — a chassis is built for a specific board footprint. Proprietary OEM boards rarely fit a generic case, and vice versa.
• Power supply format — OEM chassis usually take that vendor's own hot-plug modules, not a standard ATX unit.

Blade chassis are a different product with their own interconnect and management modules, and are listed separately.

Send us the board or the server model you are rebuilding around and we will confirm the chassis, backplane and power modules as a set.