The variety of enterprise SSD options available today

There is a large variety of enterprise flash storage options today. Can you list and describe each?

• 2.5" solid state drive (SSD) -- Uses a hard disk drive (HDD) form factor module inserted into existing servers and storage arrays. Putting flash memory into such a form factor allows it to be easily substituted for a HDD in server, blade server or external storage array.

• PCIe memory card -- This is a flash-based card that plugs directly into PCI (Peripheral Component Interconnect) bus express slots. These cards are designed to bypass legacy disk controllers and protocols that can be a performance bottleneck.

• Caching appliance -- A caching appliance sits in front of an existing storage system and frequently accessed data remains on solid state while less-used data is migrated to the traditional array.

• Tiered storage systems -- A tiered storage system includes HDDs and solid state storage, while maintaining and further optimizing large RAM caches in the controllers for increased performance. The storage controller keeps frequently accessed data in persistent solid state storage and moves inactive data to the HDD tier.

• All-SSD arrays -- All-SSD arrays typically employ solid-state drives (SSD) with form factors and electrical interfaces compatible with common HDD bays. High-performance solid state disks incorporated into existing storage array architectures can take advantage of advanced infrastructure features that vendors have been adding to these products for years. Many have management controllers the take care of all of the unique housekeeping tasks, like wear leveling algorithms, to maintain long-term performance and longevity of the hardware.