DAS, NAS, SAN? You know what they are, but how about a guide to knowing what's what? This Fast Reference gives the key points to each storage technology--including the pros and cons.

 

Type of Storage
Pros
Cons
General use
Direct-attached storage (DAS)
  • Simple
  • Low starting cost
  • Easy to use
  • Needs separate storage for each server
  • Not easy to transfer data in network
  • Server takes application processing load
  • Data and application sharing
  • Data backup
  • Archiving
Disk library
  • Fast
  • High storage capacity
  • High data availability
  • Not as easily accessible as DAS
  • Intended for write once, read rarely info
  • Disk-to-disk backup
  • Archiving
  • Near line storage
Magnetic tape
  • Low cost per megabite
  • Portable
  • Unlimited capacity (with multiple tapes)
  • Inconvienient for fast recovery of individual or group files
  • Archiving
  • Limited-budget businesses
  • Offsite storage
Network-attached storage (NAS)
  • Fast file access for multiple clients
  • Ease of data sharing
  • High storage capacity
  • Redundancy
  • Ease of drive mirroring
  • Consolidated resources
  • Less convienient than SAN for moving large blocks of data
  • Backup
  • Archiving
  • Redundant storage
Redundant array of independent disks (RAID)
  • Fast
  • High storage capacity
  • High data availability
  • Reliable
  • Security
  • Fault tolerance
  • Possible false sense of security
  • Some recovery difficulty on some systems
  • High cost for optimum systems
  • Swap files
  • Internet service providers
  • Redundant storage
Storage area network (SAN)
  • Excellent for moving large blocks of data
  • Exceptional reliability
  • Easily availible
  • Fault tolerance
  • Scalability
  • Expensive
  • Lack of standardization
  • Management complexity
  • Large databases
  • Bandwith-intensive applications
  • Mission-critical applications

This was first published in March 2006

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