Comparing SAS and SATA, Enterprise and Desktop Hard Drives for Server RAID Systems

Documentation

Content Type Product Comparison

Article ID 000005782

Last Reviewed 07/11/2022

Note

Information on this page is applicable for boards based on Intel® C602 Chipset. Please check applicable products on the bottom of this page.
If you have a current-generation Intel server product, please visit www.intel.com/support and input your product name in the search box to look for the most recent content associated with your product

This page offers key information to help you understand the differences between the two technologies. As technology rapidly advances, the information on this page may be dated and not comprehensive.

The table below provides system integrators with the key information they need to determine their hard drive requirements.

SAS vs. SATA

Requirement		SAS	SATA
Operational Availability		24 hours/day - 7 days/week	8 hours/day - 5 days/week
Workload		100%	10–20%
Cost Sensitivity		Moderately sensitive to cost	Sensitive to low cost
Performance	Latency and Seek	5.7 msec @ 15K rpm	13 msec @ 7200rpm (or smaller)
	Command Queuing and Reordering	Full	Limited
	Rotational Vibration Tolerance	Up to 21 rads/sec	Up to 5 to 12 rads/sec
	Typical I/Os per sec/drive	319	77
	Duplex Operation	Full	Half
Reliability	Bad Sector Recovery	Typical timeout is 7–15 seconds only.	Timeouts are up to 30 seconds.
	Misalignment detection	Dedicated Servo and data path processors	Single combined servo/data path processor or none
	Vibration Sensors	RV Compensation Feedback Mechanism	No RV Compensation
	Variable Sector Size	Uses a 528-byte sector and allow the I/O controller	Does not use a variable sector size (locked at 512 bytes)
	MTBF	1.2M hours at 45 degrees C	700K hours at 25 degrees C
	Internal Data Integrity Checks	End to End	Limited, none in the memory buffer
	Maximum Operating Temperature	~60 degrees C	~40 degrees C
	Warranty	~5 years	~ to 3 years
Features	Spindle Motor	Higher RPM Tighter run-out Spindle anchor at both ends	Moderate to lower RPM Lower specification for run-out Spindle anchored at one end
	Media	Full media cert	Lower media specification and density
	Head Stack Assembly	Structural rigidity Lower inertial design	Lighter weight design Higher inertial design
	Actuator Mechanics	Larger magnets Air turbulence controls RV sensors and closed loop RV suppression	Smaller magnets No air turbulence compensation No RV sensors or suppression - limited to servo wedge track alignment
	Electronics	Dual processors (dedicated servo and data path processors) Performance optimization Advanced error handling Advanced firmware algorithms	Single processor No performance optimization Standard error handling Standard Firmware algorithms
Customization	FW Code	Extensive	Limited
	Variable Sector Sizes	Yes	No
	LEDs	Yes	No

Note

Vendor implementations of these features vary between drive models. (Typical MTBF, operating temperature, and operating rotational vibration vary depending on the manufacturer). Generally the high end of the feature spectrum includes enterprise-class SAS hard drives, and the low end includes desktop-class SATA drives. Enterprise-class SATA drives fall somewhere in between.
SAS and SATA drives should not be used together in the same RAID array and should not be mixed in the same backplane.

Enterprise-class versus Desktop-class Hard Drives (PDF)
Size: 284 KB
Date: April 2016
Revision: 2.0