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4TB Hitachi Deskstar 7K4000 Hard Drive for 16TB Inside a Mac Pro

My testing is in progress on the new 4TB Hitachi Deskstar 7K4000 . OWC has them in stock and ready to ship, and graciously agreed to send me four evaluation units for testing.

Using the four standard drive bays, one can now have 16TB of internal storage! This can be arranged in many different ways: one 16TB volume, 4 X 4TB volumes, 2 X 8TB volumes, etc.

The MPG Pro Workstation is typically configured with one 2-drive stripe for the Master volume (for performance), and one 2-drive mirror for Time Machine volume (for fault tolerance), based on the assumption that 4TB of capacity is plenty to cover the most recent work— full external backups should always be made in addition.

Capacity and performance

With the 7K4000 having a 4TB capacity, I expect that average speed across the first 3 TB will be notably higher than the 3TB Hitachi 7K3000, because larger hard drives are faster (on average). In short, if you need only 3TB of capacity, getting the 4TB capacity and simply ignoring the last 1TB is likely to net you real benefits.

I started by making a 4-way RAID-0 stripe using SoftRAID 4.

Making a 4-way RAID-0 stripe with SoftRAID 4
Making a 4-way RAID-0 stripe with SoftRAID 4

Quick test

My DiskTester fill-volume test takes a long time to run (fills the entire volume), so my report will be 24-48 hours off. Get DiskTester as part of diglloydTools. I always use the command line (Terminal) version, but a simple GUI is also included.

Sequential speed

My initial testing shows outstanding speed similar to the Hitachi 3TB 7K3000. Which is plenty, because with a 5-way stripe, that Mac Pro internal bus becomes the bottleneck.

disktester run-sequential --test-size 32G ht4

Allocating maximum size contiguous file on "ht4" (14.6TB)...
14.5TB (99.9% of volume size)
TEMP FILE: /Volumes/ht4/disktester-test/DiskTester-Temporary-Test-File

Using test size of 32GB, 4MB at a time at start (0%), within a 14.5TB test file.

Iteration 1: writing...589MB/sec, reading...564MB/sec
Iteration 2: writing...579MB/sec, reading...572MB/sec
Iteration 3: writing...592MB/sec, reading...571MB/sec
Iteration 4: writing...586MB/sec, reading...571MB/sec
Iteration 5: writing...590MB/sec, reading...572MB/sec

 Wednesday, April 4, 2012 4:18:32 PM Pacific Daylight Time, volume "ht4" (14.6TB)  

------------- Averages for "ht4" (32GB/4MB, 5 iterations) ------------
Iteration 	Write MB/sec	Read MB/sec
    1     	     589    	    564    
    2     	     579    	    572    
    3     	     592    	    571    
    4     	     586    	    571    
    5     	     590    	    572    
		
 Slowest  	     579    	    564    
 Fastest  	     592    	    572    
 Average  	     587    	    570    
  Median  	     589    	    571    
  Range   	    13.0    	    8.13   

Command "run-sequential" executed in 572.69 seconds on Wednesday, April 4, 2012 4:28:05 PM Pacific Daylight Time

          
Making a 4-way RAID-0 stripe with SoftRAID 4
A 4-way RAID-0 stripe with SoftRAID 4, visual display of volume structure

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