Whether you’re a seasoned IT expert or a relative newcomer, the jargon surrounding data storage technologies can be overwhelming. That’s why we’ve selected 10 of the most popular and useful data
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Data storage term 1: Redundant array of independent
disks (RAID)
This data protection method is the most popular way to simultaneously store data on multiple
hard disks. The main advantage of RAID
is that it allows I/O requests to overlap in a way that improves performance when having to copy
one set of data to multiple locations.
Related material on RAID
- RAID levels and their pros and cons
- Comparing RAID price/performance
- Configuring RAID to your computing environment
Data storage term 2: Storage-area
network (SAN)
A SAN is a high-speed, special-purpose network (or subnetwork) that interconnects different kinds
of data storage devices with associated data servers on behalf of a larger network of users. A SAN supports
special functions such as disk mirroring, backup and restore, archiving and data migration. Fibre
Channel is the network protocol most often used for a storage-area network, although Ethernet
protocols such as iSCSI have also become viable options for SANs.
Related material on SANs
- SAN connectivity between devices
- Storage-area network basics: What to look for before purchasing a SAN
- 10 reasons to upgrade to a SAN
Data storage term 3: Primary storage
Primary storage refers to storage for data in active use, in contrast to data used for
backup or archiving purposes. Primary storage is used for the most frequently accessed data and
typically consists of the most expensive storage tiers.
Related material on primary storage
- Tips on optimizing primary storage
- Using primary storage dedupe with virtual machines
- Options for primary storage data deduplication
Data storage term 4: Tiered
storage
Based on levels of protection, performance needs, frequency of usage and other
considerations, tiered
storage technology assigns various types of data to different storage systems to achieve
greater overall efficiency and performance. For example, tier 1 data (mission-critical, recently
accessed or classified files) is typically stored on the highest performance drives available,
while tier 2 data (infrequently used or less important data) might be located on less expensive
hardware.
Related material on tiered storage
- Tips on tiering data storage
- Tiered storage strategies for the data center
- Flash SSD’s role in storage tiering
Data storage term 5: Network-attached storage (NAS)
Network-attached
storage is an individual network set up around hard disk storage for files. Because NAS isn’t
attached to the enterprise application server, storage access and management functions can be
carried out at a separate location, allowing multiple computers and processors to handle program
and storage requests separately. This results in greater overall I/O performance.
Related material on NAS
- Learn how to pick a NAS appliance
- The effect of scale-out architecture on NAS management
- Clustered and traditional NAS systems: What’s the difference?
Data storage term 6: Fibre
Channel (FC)
Designed to provide high-speed connectivity between servers and storage devices, Fibre Channel connections
can deliver speeds of 16 Gbps. Fibre Channel also offers support for devices up to six miles apart.
Fibre Channel replaced the Small Computer System Interface (SCSI) protocol for storage
networks.
Related material on Fibre Channel
- FC SANs in a virtual environment
- Pros and cons of Fibre Channel SAN zoning
- What you need to know about Fibre Channel SAN switches
Data storage term 7: Data
deduplication
Data dedupe
is a data reduction technology. It works by allowing duplicate data to be replaced with a pointer
file that redirects applications to the original file stored in a single location. For example, a
single 1 megabyte file can take the place of 100 copies of that same 1 megabyte file by
substituting 99 pointer files, resulting in potentially enormous capacity savings. This technology
is a popular way to reduce capacity requirements for functions like data backup and data archiving,
and is emerging as a way to reduce the capacity of primary storage.
Related material on data deduplication
- Dedupe best practices
- Understanding dedupe ratios in backup systems
- Using data deduplication technology eases storage requirements
Data storage term 8: Disk striping
Disk
striping technology divides data across multiple partitions and disks in computer systems.
Striping speeds data retrieval, especially when many drives are used in a RAID scheme. Striping
data across multiple hard disks improves performance because it uses hardware in all the drives in
parallel. Wide striping spreads chunks of data across multiple arrays, while narrow striping uses a
single array to spread data chunks.
Related material on disk striping
- Using striping technology in RAID systems
- Wide striping technology explained
- The advantages of doing a wide stripe with SSD storage
Data storage term 9: Logical unit number (LUN)
A logical
unit number uniquely identifies hard disk devices for use with SCSI, iSCSI and Fibre Channel
interfaces. LUNs are central to the management of block storage arrays shared over a storage-area
network.
Related material on LUNs
- Tips for managing logical unit numbers
- How to maintain LUN performance
- Virtual and thin logical unit numbers explained
Data storage term 10: Storage
virtualization
Storage virtualization
pools data from multiple physical storage network devices into one virtual location, allowing for
easier management and synchronized performance of functions like backup, archiving and recovery.
Virtualization can be implemented using software only, appliances or in the storage array.
Related material on storage virtualization
- Cut costs and increase efficiency for virtualized storage
- Storage virtualization technology explained
- How to consolidate virtualized storage
This was first published in March 2012
Storage Management Strategies for the CIO

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