Wednesday, November 30, 2022

Is Enterprise Tape a ‘Second Class’ Citizen?

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
Performance 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
Size 3.5 inch; moving to 2.5 3.5 inch 3.5 inch
Annualized Failure Rate Best Second best Worst
Bit Error Rate 1 sector in 10E16 bits 1 sector in 10E15 bits 1 sector in 10E14 bits
Cost Highest cost; usually about 8x per GB over tier 3 High cost; usually about 2x per GB tier 3 Lowest cost

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.

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