Saturday, February 18, 2012

Western Digital Green vs Black Drive Comparison

In a recent post I described my new blistering fast Windows 8 Server, which includes a parts list.  This server features a 120GB SDD SATA III 6.0Gb/s drive for the operating system and uses a single 2TB Western Digital Green SATA III 6.0Gb/s drive (WD20EARX-00PASB0) for VM and data storage.

It has been suggested by some of my readers that the WDC Green drive will not provide suitable performance compared to a WDC Black SATA III drive.  They also wondered what the true power savings is between the Green and the Black drive.  The Green drive uses less power by spinning at slower RPMs (variable ~5400 RPM vs 7200 RPM for the Black).

I decided to purchase a Western Digital Caviar Black SATA III 6.0Gb/s drive (WD2002FAEX-007BA) to run benchmarks against and compare the two drives side-by-side using HD Tune Pro 5.00 and Microsoft Exchange Server Jetstress 2010 (64 bit).

I ran each set of tests for the Green drive, then replaced it with the Black drive and ran the same set of tests on my new server.  I also ran the the tests while the server was plugged into a P3 Kill A Watt Electricity Load Meter and Monitor to accurately measure power consumption by the kilowatt-hour for comparison.

HD Tune Pro Benchmarks
The following are the benchmark test results for both drives.  The Green drive is on the left and the Black is on the right.

Benchmark Results
The Black drive delivers 17.9% better average transfer speed.  The access time was 17.6ms for the Green vs. 12.0ms for the Black.  I was surprised to see that CPU usage was much higher on the Green (6.0%) vs the Black (2.4%).


File Benchmark Results
The File Benchmark test measures read/write transfer speed using a 500MB file in 4KB blocks.  The Black drive achieved 11.5% better performance using 4KB sequential access and 28.2% better using 4KB random access.


Random Access Results
The Random Access test measures the performance of random read or write operations with varying data sizes (512 bytes - 1MB).  Again, the Black drive performed better across the board with an average 31.2% improved performance.  It also offers much better access times.

It's notable that the Green drive performed this test nearly silently, while the Black drive sounded like a Geiger Counter at Fukushima.  Neither of these drives feature AAM (Automatic Acoustic Management) so this does not impact the results (and cannot be adjusted).


Other Test Results
This benchmark runs a variety of tests which determine the most important performance parameters of the hard drive.  The Black drive offers 35.3% better random seek and 18.3% better sequential read performance.  It also has better transfer speeds from its cache.  Both drives feature a 64MB cache.



Exchange JetStress
I ran Exchange 2010 JetStress on each drive to get an accurate IOPS profile for Exchange 2010 SP2 use.  JetStress was configured for a two-hour test using a single 1TB database and one thread.

  • The Green drive achieved 47.396 IOPS with 10.751ms latency.
  • The Black drive achieved 64.57 IOPS with 15.180 latency.

I'm not sure why the Black drive's latency was higher than the Green, given the benchmark tests above, but I ran that test twice and got the same results each time.  Even so, the Black drive delivered 26.6% more IOPS.



Power Analysis
Green Drive1.10 KW at 27.5 hours
Energy use per hour = (1.1 KWH)/(27.5 hours) = 0.04 KWH per hour of use
Energy use per day = (0.04 KWH/hour)(24 hours/day) = 0.96 KWH over a full day
Cost per day = (0.96 KWH)(18.5 cents/KWH) =  17.8 cents per day

Energy use per year = (0.96 KWH/day)(365 days/year) = 350 KWH/year
Cost per year = (350 KWH/year)(18.5 cents/KWH) = $64.82 per year.

350 KWH = ~700 lbs of greenhouse gas to the atmosphere per year.

Black Drive0.72 at 14.75 hours
Energy use per hour = (0.72 KWH)/(14.75 hours) = 0.049 KWH per hour of use
Energy use per day = (0.049 KWH/hour)(24 hours/day) = 1.18 KWH over a full day
Cost per day = (1.18 KWH)(18.5 cents/KWH) =  21.83 cents per day

Energy use per year = (1.18 KWH/day)(365 days/year) = 431 KWH/year
Cost per year = (431 KWH/year)(18.5 cents/KWH) = $79.74 per year.

431 KWH = ~860 lbs of greenhouse gas to the atmosphere per year.

Result: The WDC Green drive uses 18.8% less energy than the Black drive.



Conclusion
It's obvious from the test results above that the Western Digital Caviar Black drive performs better than the Green drive.  At the time of this writing the Green drive costs $139 and the Black is $249.  That's a 44% premium for a drive that performs on average 24% better.

In real-life observations I don't really see that much difference in performance between the two at this time.  However, this Hyper-V server has twice as much RAM as my last server so it will potentially be hosting many more VMs (and will have a higher IO load).  For this reason I decided to keep the Black drive, even though it costs more, it's a bit noisier when it's working hard and uses more energy.  I like muscle cars, too.  :)

If you plan to do RAID, I would most definitely recommend the Black drive because it spins at a consistent 7200 RPM.  Reports say that the variable RPMs on the Green drive can cause read/write errors.

I hope you find this information useful.

Wednesday, February 8, 2012

How to Disable Lync Mobility for Some Users

The Lync mobile client allows users to connect to Lync using a mobile device.  Microsoft has developed free Lync mobile clients for Windows Phone, Apple IOS, Android and Symbian.  Check your device's marketplace for the free download.

Some organizations may require that Lync mobility is only enabled or disabled for certain users.  Common reasons may be to facilitate a controlled Lync mobile deployment or to prevent non-exempt employees from accessing Lync after hours.  This article explains how to configure this.

First, it is assumed that Lync Mobility is configured and working in your environment.  If you need help with this, see Deploying the Lync 2010 Mobility Service by Lync MVP Jeff Schertz.

By default, all Lync users can access Lync with Lync Mobile once the mobility services are installed.  To change this behavior we will be configuring a new Client Version Policy using the Lync Server 2010 Control Panel. 

You will normally only see a Global client version policy.  This policy displays all the allowed User Agents and the minimum versions allowed by Lync.  Once you install Lync Mobility you will see a new user agent type, MCX, that allows all user agents greater than 4.x.x.x.




If your goal is to enable Lync mobile for certain users:
  • Open the Lync Control Panel as a Lync administrator. Select the Clients node on the left and select the Client Version Policy at the top. 
  • Change the Global client version policy to disallow Lync mobile connections:
    • Edit the Global client version policy by clicking Edit in the menu bar
    • Select then MCX user agent (you may need to scroll to locate it) and select Show Details in the menu bar
    • Edit the MCX Client Version Rule so that the Major Version is 0 (zero)
    • Click OK to close the rule and then click Commit.  At this point Lync Mobile is disabled for all users.
  • Create a new User client version policy to allow Lync mobile connections:
    • Click New > User Policy to create a new User Client Version Policy.
    • Name the new policy Lync Mobile Users and enter a description for the new policy
    • Select the MCX user agent and verify that the version is 4.*.*.*
    • Click Commit to save the new user version policy
  • Assign the Lync Mobile Users client version policy to selected users:
    • Click the Users node in Lync Control Panel
    • Edit the Lync user(s) who will be enabled for Lync mobile
    • Assign the Lync Mobile Users policy as the Client Version Policy, as shown below, and click Commit

If your goal is to disable Lync mobile for certain users:
  • Open the Lync Control Panel as a Lync administrator. Select the Clients node on the left and select the Client Version Policy at the top. 
  • Create a new User client version policy to disallow Lync mobile connections:
    • Click New > User Policy to create a new User Client Version Policy.
    • Name the new policy Disable Lync Mobile and enter a description for the new policy
    • Edit the Client Version Rule for the MCX user agent so that the Major Version is 0 (zero)
    • Click Commit to save the new user version policy
  • Assign the Lync Mobile Users client version policy to selected users:
    • Click the Users node in Lync Control Panel
    • Edit the Lync user(s) who will be disabled for Lync mobile
    • Assign the Lync Mobile Users policy as the Client Version Policy and click Commit

[This article was suggested by reader @jshoq. Thanks for the suggestion!]