Help Me Choose: Hard Drives and Solid-state Drives
Solid-state Drives (SSD): Fast storage medium for random I/O (input/output)
10K and 15K SAS drives: Performance and availability for mission critical applications
Nearline SAS and Enterprise SATA drives: High-capacity and exceptional $/GB for business critical applications
Dell puts its Enterprise Hard Drive and Solid-state Drive offerings through a rigorous validation process before they are ever considered as additions to our line of server and storage systems. Dell has stringent drive specifications for performance, duty cycles, mean time between failure (MTBF) and rotational vibration, which are all necessary for an enterprise-level environment.These types of exacting specifications must be met before we will make them available for customer usage.
Solid-state Drives are designed to support customers with a need for higher performance, endurance and lower power consumption in mission critical enterprise applications.
|Below are a number of charts comparing the various HDD drive types. Generally speaking, the mission critical (MC) drives (10K and 15K SAS) are used in those application requiring the highest reliability and performance. Business critical (BC) drives (7.2K Nearline SAS and SATA) provide much higher capacities, but lower reliability and performance when compared to MC.|
The direction of the MC drive industry appears to be trending towards development of 2.5” drives only. If this occurs, it is possible that the 3.5” drives may have reached their maximum capacity (600GB) and may not have additional development activity that would increase their existing capacity, improve performance or reduce power requirements. In this event, chances are that production of the 3.5” MC drives will cease sometime in the future. The charts below show the advantages of 2.5” MC vs. 3.5” MC in most cases, and these advantages may increase in the future as further development on 2.5” MC occurs.
Our recommendation to customers reviewing standard configurations for Dell™ servers consider including 2.5” 10K/15K over 3.5” 15K HDDs
|I/O operations per second (IOPs) is a recognized measurement of random I/O performance for HDDs. The chart below illustrates the differences between the various HDDs from 2.5” 15K at the top and 3.5” 7.2K at the bottom:|
Power requirements show the advantage of 2.5” 7.2K drives and the disadvantage of 3.5” 15K:
Combining these two charts into an IOPs/Watt measurement results in the following:
If there is concern about how much performance can be gained from drives in a given amount of rack space, consider the following graph where it is assumed twice as many 2.5” drives can fit in the same space as 3.5” drives. Clearly IOPs for the 2.5” mission critical drives dominate.
NLSAS and SATA business critical drives have clear advantages over mission critical for considerations of cost and maximum capacities. The chart below on cost illustrates the lower cost of 3.5” 7.2K drives and the higher cost of 2.5” 15K drives.
Relative capacity points for each drive category are shown in the chart below. Note that it is expected that capacities will increase for each category but is not anticipated for the 3.5” 15K drives.
If you are interested in an SSD for the enterprise environment, there are different types of drives, depending on the access and performance that you require.
Dell Value 2.5” SATA SSDs are suitable for customers that have mixed workloads such as data warehousing, virtual desktop and high-performance computing applications. These drives are offered in capacities of 100GB and 200GB and have been designed for compatibility and ease of integration into Dell servers.
The Dell Mainstream 2.5” SAS SSDs are a good solution for customers who manage online transactional processing (OLTP), databases, business decision support systems and data caching applications, which may have extremely high write intensive workloads. These drives are offered in capacities of 200GB and 400GB. They have been designed for compatibility and ease of integration into new or existing tier-0 enterprise storage systems, including servers, direct-attached storage and network-attached storage.