Hard Disk Drive Performance Degradation Susceptibility to Acoustics (ASHRAE TC 9.9 White Paper)

Overview

This document is a 2019 white paper from the ASHRAE TC 9.9 technical committee. Its subject is how acoustic and vibration excitation from server fans and blowers degrades the throughput of hard disk drives (HDDs). The paper is a free download from ASHRAE but all rights are reserved, and ASHRAE prohibits entering its content into AI tools. This record rests only on metadata and short summaries; contributors from Seagate, Dell, IBM and Intel are acknowledged in the paper's front matter.

According to the Mechanisms section, sound pressure level scales with roughly the fifth power of fan speed, that is, about 50 log10 of the speed ratio in dB. For blowers the factor is about 70 log10. HDDs show sensitivity up to about 20 kHz, while servo correction is effective only below about 2 kHz. This gap means that high-frequency acoustic energy can disturb head positioning while the servo system cannot compensate for it.

The Trends section stresses that higher equipment power drives higher air-mover speeds, which increases the acoustic risk to HDDs. In other words, as IT equipment power density grows, fans speeding up to reject heat create a side effect that threatens storage performance. The paper's table of contents covers HDD susceptibility to external disturbances, trends in airflow demand and implications for total cost of ownership (TCO).

The limit of the record is that the paper's numerical results and test data are not here; only the mechanism and trend summary is. The paper makes visible a hidden effect on storage performance of design decisions moving towards higher inlet temperatures and higher density. The paper itself should be consulted for details.

Key points

1. Sound pressure level scales with roughly the fifth power of fan speed (about 50 log10 of the speed ratio, in dB); about 70 log10 for blowers.
2. HDDs show sensitivity up to about 20 kHz while servo correction is effective only below about 2 kHz.
3. Higher equipment power drives higher air-mover speeds, increasing acoustic risk to HDDs.
4. Contributors from Seagate, Dell, IBM and Intel are acknowledged in the front matter.
5. Contents: HDD susceptibility to external disturbances, airflow-demand trends and TCO implications.

Using it in design

• Warn when high inlet temperatures (driving fan speed-up) are combined with HDD-heavy storage racks.
• Consider the acoustic effect when deciding to raise set points.
• Keep it in mind for gas suppression design too, since inert-gas discharge noise is relevant.

Who should read it

Data center designers and operations engineers who set cooling set points and fan speeds in storage-heavy halls.

Publication details

Authors

ASHRAE TC 9.9

Publisher

ASHRAE

Year

2019

Document number

TC 9.9 White Paper

Document language

English

Source type

Standard

Access

Free to read

Licence

Copyright retained; citation only — the publisher’s terms apply to the original document

Citation