Quick glossary: Storage
January 8, 2018
Storage has always been a key aspect of data management in the enterprise. Now, in the era of big data, understanding storage options and technologies has taken on an even greater significance. This glossary offers 30 essential terms that will help you tune up your storage vocabulary.
From the glossary:
Active:active / active:passive
All modern enterprise storage arrays include controllers (servers) that move data between their drives and the external network. If all controllers are working all the time, it’s an active:active system. If half the controllers are working all the time and the other half are on standby, it’s an active:passive system. Controversy rages at storage companies when their marketing and sales staff disagree over which parts of the controllers are active or passive in various situations.
You know about bits, bytes, megabytes, kilobytes, gigabytes, and terabytes. You may know about petabytes (1,024 terabytes) if your organization is massive enough. What comes next? Exabytes (1,024 terabytes), zettabytes (1,024 exabytes), yottabytes (1,024 zettabytes), and brontobytes (1,024 yottabytes). You’ll probably never need more, but that’s what we thought about double-sided floppy disks.
Non-volatile memory express (NVMe)
NVMe is an emerging standard for using PCI connections rather than the older, slower Advanced Host Controller Interface to connect hard drives to processors and memory. By changing these connections to PCI, processors/memory can make better use of the solid-state (flash) drives’ speed advantage vs. conventional hard disks. There’s also a fiber channel version in the works.
This is the concept of using software policies to keep your data on the medium that’s most appropriate to its nature. Fresh and important data might be readily available on enterprise-class SSDs in your SAN; in-between data may live on serial ATA drives on an older, slower SAN or NAS (or on your cloud); while long-term retention is relegated to the tape library. This is only an example; companies can tier their data up, down, or sideways in many combinations. Tiering software helps storage managers devise policies and puts them into motion.