Solid-state storage isn't limited to being a drop-in replacement for spinning disk -- the technology is flexible enough to fit on a PCIe card, mounted as a chip into a motherboard and more. In this Storage Decisions video, Dennis Martin, president and founder of the analyst firm Demartek, outlines the major types of form factors for solid-state storage.
Among SSD-specific form factors, mSATA, which was developed in 2009, uses an interface similar to a mini-PCIe interface, according to Martin. It was originally intended to be used with hard disk drives (HDDs) as well, but solid-state won out. "It was originally intended as both a hard drive and an SSD form factor, just a little tiny one, but the hard drive guys just said, 'Hey, this doesn't make sense for us to do this,' so really now it's an SSD form factor."
MicroSSD -- which looks like chips soldered to a motherboard -- was introduced in 2011, and is designed for use in mobile platforms like tablets and ultrabooks, according to Martin.
"The physical interface looks different, but the OS sees a SATA device," said Martin. "[They also require] very low power, by the way, which is what you want on a laptop, because you want battery life."
Martin also discusses the range of interfaces used on solid-state devices using a disk-drive-style form factor, including SATA II, SAS, SCSI Express, IDE/PATA and Fibre Channel. He noted that the most common form factor for SSDs is the 2.5-inch drive form factor -- but thicknesses can vary on individual units.
PCI Express (PCIe) cards allow solid-state storage to take advantage of a PCIe bus, but Martin said administrators have to be sure an SSD card is compatible with existing hardware.
"Couple things to think about -- make sure it fits. If you've got a big, full-height, full-length card and you've got a low-profile server [that] doesn't give you full length, you won't be able to put that card in it. The other thing is that some of these large PCIe SSDs draw more power than the bus provides. [With] some of the buses, 25 watts is all you get. If the SSD needs more than that, you're going to need to get power from somewhere else," he said.
Another option for solid-state storage is the DIMM form factor, similar to what is used for computer memory. Martin said SATA DIMM SSDs can fit DIMM sockets, and he suggested using SATA DIMM SSDs in slots that are not filled with memory to take advantage of additional storage space.