The data storage networking industry has been moving strongly toward disk tiers, but has anyone given any thought to doing the same for tape?
We have all heard for years about tiered data storage for disk arrays. Tier 1 is usually enterprise disk, which was once Fibre Channel
but more and more is becoming SAS
. Tier 2 is typically enterprise SATA
, while tier 3 might be consumer-grade drives. And the last year or two has seen the rise of a tier 0 for flash-based solid state drives (SSDs
There are big differences between each of the tiers in terms of reliability, performance, data integrity and cost, especially for tier 0 SSDs. Here is a quick review of some of the major differences between the disk tiers:
|Drive type and interface
||Tier 1 FC and SAS
||Tier 2 SATA
||Tier 3 SATA
||Best transfer rates and best seek and latency time
||2x seek and latency time; 25% less performance
||Seek time is the same as tier 2, but lower performance
||3.5 inch; moving to 2.5
|Annualized Failure Rate
|Bit Error Rate
||1 sector in 10E16 bits
||1 sector in 10E15 bits
||1 sector in 10E14 bits
||Highest cost; usually about 8x per GB over tier 3
||High cost; usually about 2x per GB tier 3
This table does not include SSDs, of course, which have a wide range of reliability and performance and might need their own tiers.
Read the rest at Enterprise Storage Forum.