Western Digital Storage Platforms
Ultrastar Platform Innovations
Engineering innovations that deliver real-world benefits:
- Reliability
- Better cooling, lower fan speed, less noise
- Reduced power consumption, lower utility bills
The Problem with Dense HDD Shelves
Air is heated by successive rows of drives:
- The front drives stay relatively cool
- The rear drives get progressively hotter
- Additional blowers required at the front
Results in:
- Higher power required
- Higher energy cost
- Higher noise levels
- Higher vibration leading to performance degradation
- Higher temperatures likely affecting reliability
Ultrastar Data102 is Different
Dividing the enclosure into 2 thermal zones for HDDs:
- An innovative airflow management system is used to maintain safe working temperatures
- Warmed air from the front zone is ducted away from the rear drives
- Cool air is drawn into the center of the enclosure for the rear zone
ArcticFlow Technology at Work
Dividing the enclosure into 2 thermal zones for HDDs:
- Front Half: 3 rows x 14 drives + 1 row x 12 drives (54 drives)
- Rear Half: 4 rows x 12 drives (48 drives)
- Cold air tunneled directly into center of platform to cool last 4 rows of drives
- Benefit: Enables lower fan speed to maintain cooling
- Lower power required
- Lower noise levels
– Lower fan vibration
- Lower operating temperatures help enable 5-year limited warranty
Why Vibration Control is Important
- The high density of current HDDs comes from ever higher track density
- Extremely tight tolerances on positioning the read/write head correctly over the data track
- External shock and vibration can cause the head to go off track
- The external shock and vibration can come from other shelves in the rack being serviced, from the door being closed or a fork lift passing
- In a dense array of HDDs, adjacent drives seeking at high speed can induce vibration into their neighbors
- Fans can induce vibration through the chassis and also through the air as sound energy
- The shock and vibration is detected by sensors on the drive to protect data
- For reads, the head has to resettle and wait for the correct sector to come around again so that reading can continue
- For writes, the write gate is shut off so that adjacent tracks are not corrupted. Then the head has to resettle and wait for the correct sector to come around again so that the data can be written in the correct place
- The overall effect is that application performance is reduced as additional disk latency is introduced to almost every operation
Innovative IsoVibe at Work
- Precise cuts in the baseboard provide "suspension" for the HDDs
- Isolation of the drives reduces the vibration transmitted from one drive to another
- Vibration-isolated fans also minimize vibration
- ArcticFlow reduces vibration by allowing lower fan speeds
- Performance is maintained across the platform, even when all the drives are working hard
- Shock and vibration control is a significant design consideration in Western Digital platform design
- IsoVibe will allow for future HDDs with even tighter track densities to operate at full performance