An enterprise SSD (enterprise solid-state drive, also sometimes referred to as an enterprise solid-state disk) is a device that stores data persistently or caches data temporarily in nonvolatile semiconductor memory and is intended for use in storage systems, servers, and direct-attached storage (DAS) devices.
Characteristics distinguishing enterprise SSDs from consumer or client SSDs used in devices such as PCs, laptops, and tablet computers may vary by manufacturer and industry market research firm. Examples of advantages that an enterprise SSD may offer over a client or consumer SSD include higher performance, protection of DRAM-stored data in the event of a power loss, stronger error correction code (ECC), consistent and persistent quality of service, and a lengthier warranty.
An enterprise SSD also tends to provide a greater level of endurance than a client or consumer SSD. NAND flash wear-out can occur due to the repeated program/erase process necessary to write new data to a chip. Manufacturers have improved NAND flash endurance over time through techniques such as wear-leveling algorithms, self-healing capabilities, and overprovisioning. Through overprovisioning, an enterprise SSD may reserve a greater percentage of NAND flash for use in the event of chip wear-out or failure.
The earliest enterprise SSDs often used single-level cell (SLC) NAND flash, which stores one bit per cell and offers the highest levels of performance and endurance, with a typical lifecycle of 100,000 writes per cell. The improvements to NAND flash technology have enabled enterprise SSD manufacturers to use lower-endurance NAND flash options such as multilevel cell MLC, triple-level cell (TLC), and 3D NAND. Advantages of the lower-endurance forms of NAND flash include lower cost and higher capacity.
SSD manufacturers sometimes offer different endurance options with their enterprise products. For instance, a vendor might sell an enterprise SSD with a high-capacity option intended for read-intensive application workloads. Such a high-capacity enterprise SSD might offer an endurance of only one full drive write per day (DWPD), meaning the drive can write and rewrite data to full capacity once a day for the warrantied lifespan of the drive. Another enterprise SSD option from the same product family might support 25 DWPD at a lower capacity for use with write-intensive workloads.
Enterprise SSDs are available in a variety of form factors and interface types. Interface options include serial ATA (SATA), serial-attached SCSI (SAS) and PCI Express (PCIe) to transfer data to and from the central processing unit (CPU). Form factors include a 2.5-inch drive that fits into the same slot as an HDD, a half-height half-length (HHHL) add-in card or an M.2 module that plugs into a computer's PCIe bus, and a dual in-line memory module (DIMM) with chips on a small circuit board that connects to a computer's motherboard.