Enterprise-class versus Desktop-class Hard Drives

Revision 1.0

Enterprise versus Desktop Hard Drives

Hard Drive Features

To meet operational requirements, some vendors and drive models have significant differences

in disk drive design for desktop class hard drives compared to enterprise class hard drives.

This document examines these differences and describes how the drive design and feature set

meet the needs of the two usage models. This document will contrast drive class differences in

general terms, and will give a general description of features and methods used by drive

vendors to meet these differing needs. This document will not specify vendor specific features

or design implementations. Actual drive models may contain a mixture of the features that are

described. For example, a particular desktop class drive model may include some enterprise

class drive features, and some enterprise class drive models may not include all enterprise

class features.

1.1.1 Operational Availability and Work Load

Desktop class systems normally have one hard disk drive, or a mirrored set of drives that are

designed to work in a less demanding environment. The drive is only accessed to provide

program or application access, access the swap file, or complete a limited data save or data

retrieval for the operating system or running application. The system is usually shut down

during the evening and weekend hours, or left idle for long periods of time.

An enterprise system may control multiple drives that add both capacity and redundancy to a

storage subsystem. For example, an enterprise system may use four drives in a RAID 10 for

the operating system and may use many drives for configuration in multiple RAID 5 or RAID 6

arrays to hold client data. The enterprise system will not only perform operating system and

application tasks locally, but will also be expected to support client requests 100% of the time.

During off peak time the enterprise system may be involved in patrolling the hard drives for

defects or errors, system backup, and other maintenance tasks. Enterprise workloads create

greater wear on bearings, motors, actuators, and platter media; which generates additional heat

and additional vibration. Enterprise class drives are designed with heavy duty components and

drive firmware programming to meet the rigors of this environment.

1.1.2 Cost Sensitivity

Desktop systems are very price sensitive, driven in part because the ratio of clients to servers is

much higher. Clients run user-oriented applications that place a lighter and intermittent load on

the local drive(s). Enterprise systems are not as price sensitive because they are typically

running multiple enterprise applications and must handle a higher work load with increased

reliability and availability. These enterprise-class systems usually include a higher drive count.

The features required to support the additional work load add cost to the drive system design.

1.1.3 Performance

Enterprise-class drives generally incorporate internal mechanisms that allow faster data access

and retrieval. These features include heavier actuator magnets, faster spindle speeds, denser

magnetic media, and faster drive electronic components with more cache memory and faster

hard drive micro-processor speeds.