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20051215 Thursday December 15, 2005

Sun T2000 vs Dell 6850: LDAP AuthRate

As I mentioned in my last post, at the Sun Fire™ T2000 launch last week, we had our own demo at the Austin campus to help show it off. We pitted the T2000 against the Dell PowerEdge™ 6850 server, which we believe to be the best system that Dell has to offer. Here's a side-by-side comparison of the system specs:

  Dell PowerEdge™ 6850 Sun Fire™ T2000
CPU Type Intel® Xeon® EM64T UltraSPARC® T1
with CoolThreads™ technology
Total CPU Sockets 4 1
Total CPU Cores 8 8
Total Hardware Threads 8 32
CPU Clock Rate (GHz) 3.2 1.0
DDR2 Memory Available (GB) 32 32
System Height (Rack Units) 4 2
Approx. Idle Power Draw (Watts) 320 220
Approx. Loaded Power Draw (Watts) 600 267
Operating System (Pre-Installed) Microsoft® Windows® Server 2003 Standard
x64 Edition
Sun Solaris™ 10 3/05 HW 2
List Price (US Dollars) $33,652 $25,995


A few notes on the information in this table:
  • The Sun Fire™ T2000 server usually ships with a 1.2 GHz UltraSPARC T1 processor. However, as this was a pre-release system we only had a 1.0 GHz processor.
  • The Dell PowerEdge™ 6850 was actually observed to draw in excess of 640 Watts under load. However, for the purpose of the SWaP calculation, a value of 600 Watts was used.
  • The Dell PowerEdge™ 6850 was actually observed to draw in excess of 640 Watts under load. However, for the purpose of the SWaP calculation, a value of 600 Watts was used. It should also be noted that this system requires 200-240VAC power.
  • The Sun Fire™ T2000 was actually observed to draw around 240 Watts under load. However, the system spec sheet lists a maximum consumption of 267 Watts, and therefore that value was used for our SWaP calculations.
  • The provided list price for the Sun Fire™ T2000 server is for a system with a 1.2 GHz CPU whereas the system we were testing had only a 1.0 GHz processor.

In order to compare the performance of these two systems, we measured LDAP authentication performance running the Sun Java™ System Directory Server 5.2 patch 4. The workload for this test was very similar to that used by the SLAMD LDAP Weighted AuthRate job, but because this was a public demo, we used a custom client to show the relative performance of these systems in real time (I may be able to post a Shockwave Flash recording of this demo later this week). In this workload, each authentication consists of a subtree equality LDAP search operation on an indexed attribute (in order to locate the user entry based on a login ID) followed by a bind as that user. The login ID value for each authentication was selected at random from the entire data set, with a weighted access pattern such that 80% of the search operations were targeted at a set of 20% of the user entries, which reflects many measured real-world access patterns. Two Sun Fire™ V20z servers were used to generate the load against the Directory Server instances (1 V20z for each server).

The Directory Server instances were installed and optimally tuned for each system. A total of 250,000 user entries (generated using the MakeLDIF tool provided with SLAMD using the default example.template template file) were loaded into each directory. We would have used a much larger number of entries, but this is near the maximum cacheable amount for our Directory Server on a Windows system, and exceeding that would have given the T2000 system a large unfair advantage. In fact, tests with a data set of 1 million users showed that the server running on the T2000 system was able to achieve even higher authentication performance than with a set of 250,000 users, whereas the server on the Dell system exhibited severely degraded performance compared with that measured with a set of 250,000 users.

Each server was asked to process a total of 250,000 user authentications as quickly as possible. Both total length of time required to process these operations and the average number of authentications per second were measured. The average number of authentications per second was used as the "performance" component of the SWaP (space, Watts, and performance) metric. The SWaP value for each system was calculated by dividing the average number of authentications per second by the product of the space consumed (in rack units) and the power consumption under load (in Watts).

The maximum LDAP authentication performance that we were able to achieve from each system is as follows:

  Dell PowerEdge™ 6850 Sun Fire™ T2000
Performance (LDAP auths/second) 2853.34 8067.58
Total Processing Time (seconds) 87.65 31.00
SWaP 1.19 15.11


As can be seen from this information, when it comes to LDAP authentication performance the Sun Fire™ T2000 server beats the Dell PowerEdge™ 6850 server in all areas that we compared:
  • The Sun Fire™ T2000 server delivers over 2.8 times better LDAP authentication performance than the Dell PowerEdge™ 6850, even when you consider that the Sun system only had a 1.0 GHz processor whereas the T2000 normally comes with a 1.2 GHz processor.
  • The list price for the Sun Fire™ T2000 server is $7657 less than the list price for the Dell PowerEdge™ 6850 server, even when you consider that the price for the Sun system includes a faster CPU than the one that we were able to test.
  • The Dell PowerEdge™ 6850 requires twice as much rack space as the Sun Fire™ T2000 server.
  • The Dell PowerEdge™ 6850 consumes nearly 1.5 times as much power (measured in Watts) than the Sun Fire™ T2000 server when both systems are idle.
  • The Dell PowerEdge™ 6850 consumes 2.25 times as much power (measured in Watts) under load as the Sun Fire™ T2000 server, even with an optimistic estimate for the Dell system and a pessimistic estimate for the Sun system.
  • The Dell PowerEdge™ 6850 system requires 200-240VAC power, which is less commonly-available than 110V power, particularly in environments that typically run on x86/x64 systems. The Sun Fire™ T2000 server accepts 100-240VAC power and therefore can use standard 110V circuits.

When you look at any one of these metrics, the Sun Fire™ T2000 certainly looks attractive. However, the real value of this system is even more apparent if you compare what you would need in order to meet a given level of performance. For example, if your directory environment needs to be able to handle 10,000 authentications per second under peak load, then a solution with two Sun Fire™ T2000 systems would be over $82000 cheaper to buy up front than the four Dell PowerEdge™ 6850 systems that would be required, and you'd also save more than 1.8 kiloWatts of power and 12 rack units of space with the Sun solution.

Posted by cn_equals_directory_manager ( Dec 15 2005, 11:46:33 PM CST ) Permalink Comments [7]


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