Recently I did a little trade deal and ended up with eight HGST 3 TB SAS drives. They’re old, very old. 2012 old — yikes! But I think they’ve been sitting a few years, so maybe they don’t have crazy hours on them.
These aren’t bad drives, especially in today’s market with the insane price hikes. Each disk is 3 TB, 3.5″ and 7,200 RPM. Benchmarked individually I was getting a consistent read speed of 150 MB/sec. Not bad!
The elephant in the room though, how much power do these suckers pull? I set up an old machine to benchtest that. Here is the data I got, power figures are total system power @ the wall socket, with a Kill-A-Watt meter.
The drives were cheap… next to nothing. Basically with the trade I did, each one cost me less than $10. The HBA was $18 shipped and the SAS breakout cable was $13 shipped. All readily available on eBay.
Power Figures
Baseline without HBA: 30W
Baseline /w HBA installed : 37 W
1 SAS disk: 44 W (+7 W)
2 SAS disks: 55 W (+11 W)
3 SAS disks: 65 W (+10 W)
4 SAS disks: 75 W (+10 W)
4 SAS + 1 SATA 3.5″ disk: 81 W (+6 W for SATA)
Observations:
Incremental power per SAS disk: ~ +10 W idle
SATA disk only adds ~+6 W idle
Test Bed System Specs:
Intel Core i5 4570 Haswell Quad Core
2x 4 GB DDR3 RAM — 8 GB Total
8 GB SATA DOM / SSD for the OS
LSI Logic SAS2308 Fusion-MPT SAS-2
Xubuntu 16.04 — doesn’t matter much here, but incl for completeness
750W No-Name Power Supply
NOTE:
All readings are steady-state idle; initial spin-up or seek currents are not included. Power scaling is roughly linear with the number of disks… So the data is likely fairly accurate.
Lets look at some early performance figures…
Now… that doesn’t look super impressive. But, if we tweak for larger test size…
That’s more like it! That is with four disks in a RAID 0 stripe. This isn’t how you’d normally be using them, but I’m more so curious what this old hardware can do and RAID0 will show the best case example of that.
Decent performance… if they used less power, I’d say it would be very attractive for a good way to add:
8 drives: $124 for 24 TB RAW (1 HBA, 8 drives, 2 cables)
4 drives: $70 for 12 TB RAW (1 HBA, 8 drives, 1 cable)