You may need to calculate the power consumption and heat dissipation of a new storage susbsystem to see if your power load center and air conditioning can support the additional load, so you refer to the VessRAID datasheets. The VessRAID 1840 datasheets list the following power information:
VR1840i
Current (Maximum): 7/8A (100V); 3.5/4A (240V)
Power Consumption: 242.8Watts (w/ SAS drives), 72.2Watts (w/o drives)
VR1840f
Current (Maximum): 8A (100V); 4A (240V)
Power Consumption: 241.8Watts (w/ SAS drives), 51.3Watts (w/o drives)
For 120VAC operation the maximum possible current that the two power supplies could draw is:
450W / 120VAC = 3.75A each, for a total of 7.5A @ 120VAC or 3.75A @ 240VAC
However the total peak (worst case) current draw on the power supplies by the subsystem with 16 15K RPM SAS drives is around 3.75A @ 120VAC or 1.57A @ 240VAC.
This is based on the total startup load of the 16 SAS drives and the startup load of the RAID controller and the enclosure, which is approximately 120W: 256W + 120W = 376W / 120V = 3.75A.
For 16 SATA drives the startup load would be: 144W + 120W = 264W / 120V = 2.2A.
This startup load is momentary and is well within the design limits of the power supply units.
More important for these load and heat calculations is the operational average, or how much power will be used during operation.
The overall startup and operational loads will vary with the drive type used in the enclosure; here are some typical 2TB drive power consumption values:
| Type |
RPM |
Typical W |
Idle W |
| SAS | 15K |
16 | 12 |
| SAS | 7200 | 10 | 7 |
| SATA | 7200 | 9 | 6 |
For 1TB drives the power used is approximately 20% less, and for 500GB drives 40% less.
From the datasheets we can see that the operational average for the two product versions are 72W and 51W without any drives.
To calculate the typical power consumption of the VessRAID iSCSI subsystem:
16 SAS drives @ 16W = 256W + Controller @ 72W = 328W
16 SATA drives @ 9W = 144W + Controller @ 72W = 249W
To calculate the approximate BTUs generated for any cooling requirements:
16 SAS drives: Heat dissipation = 328W x 3.413 = 1120 BTU
16 SATA drives: Heat dissipation = 249W x 3.413 = 850 BTU
For the VessJBOD the IO module consumes around 20W, so just subtract 52W from these results.
To calculate the typical power consumption of the VessRAID FC8 subsystem:
16 SAS drives @ 16W = 256W + Controller @ 51W = 307W
16 SATA drives @ 9W = 144W + Controller @ 51W = 195W
To calculate the approximate BTUs generated for any cooling requirements:
16 SAS drives: Heat dissipation = 307W x 3.413 = 1048 BTU
16 SATA drives: Heat dissipation = 195W x 3.413 = 666 BTU
For the VessJBOD the IO module consumes around 20W, so just subtract 31W from these results.
