Small Business IT Blog

SATA vs SAS - What is the difference?

Posted by Sean Kline on Thu, May 12, 2011 @ 04:35 PM

Deciding between SATA vs SAS is important when considering the right storage infrastructure for such key projects as server virtualization for small business.  SATA or Serial ATA stands for Serial Advanced Technology Attachment and is the next generation computer bus interface from the parallel interface ATA.  SAS, or Serial Attached SCSI, is a faster and historically more expensive interface.

sata vs sas

Because SAS drives are able to rotate so much faster (up to 15K RPM) than SATA drives (typically 7.2K RPM), seek times may be substantially faster by more than 2 times.  The figure above shows different capacities and list prices of SAS and SATA drives available for a particular flavor of HP DL380 G7.  While SATA is the least expensive drive available, for servers, it is typically much better to go with SAS for low capacity use cases.  For example, a 10K 146GB SAS drive is not much more expensive than the substantially slower 146GB 7.2K SATA drive.

At higher capacities, high performance SAS drives climb in price steeply.  It may be better to take advantage of dedicated storage infrastructure such as Network Attached Storage (NAS) or a Storage Area Network (SAN), rather than populate a server with expensive direct attached storage.

As discussed in an almost identically titled blog entry - SAS vs SATA – what’s the difference? - SATA drives tend to be better solutions for desktops and SAS drives for servers. 

Key takeaways:

  • The performance benefits of SAS far outweigh the price difference at low capacities
  • There is a point of diminishing returns for the performance of SAS at high capacities
  • SATA tends to be a better solution for desktops and SAS for servers
  • Consider a dedicated storage infrastructure for high capacity needs

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Topics: Storage Virtualization, Virtualization, Storage