What is the difference between Enterprise and Consumer Desktop hard drives?
Enterprise and Consumer (or ordinary desktop) hard drives are different in several key ways.
We do not recommend the use of desktop hard drives in servers or mission critical systems at any time.
Desktop, or Consumer Hard Drives
The drives are suited to desktop workloads. They are not designed for heavy use, or 24x7 access. Cost optimised desktop drives are suited to single usage (i.e. there is one user using that machine, as opposed to servers where multiple access can be requested at the same time) and lower power draw.
Desktop drives do not feature RAID protection features such as TLER (time limited error recovery).
Enterprise Hard Drives
Enterprise SATA and all SAS drives are designed for heavier usage and are built or tested with higher reliability in mind. Manufacturers of these drives usually quote higher reliability in the form of Mean time Between Failures (MTBF) and certify them for 24x7 access.
Enterprise drives feature TLER. In the event of a media or other problem, the drive will only attempt to resolve the problem internally for at most 6 seconds. At the end of that time, the drive will hand over error management to the RAID controller. The drive will not go offline to complete "heroic recovery".
This prevents the situation where a desktop drive could retry almost indefinitely to read the data. This would keep the RAID controller in a timeout state where it could not easily determine the state of the drive. This would introduce performance problems, as well as possibly eventually forcing the entire drive out of the RAID array even if it is just one sector that is damaged.
Enterprise drives will attempt to stay online while the RAID controller can either remap the sector, or notify the user of a need to replace the drive at the nearest opportunity. Data remains protected especially if you are using RAID 6.
Note: Seagate Constellation, or Seagate NS drives are example of Seagate Enterprise drives. Western Digital RE and RE4 drives are example of Western Digital's equivalent. WD Caviar Black drives feature a more reliable mechanism but are still designed for desktop use and do not feature TLER.
Applies to:
- All server and desktop systems capable of RAID functionality.
