SteveOH

I recently came across an application provided by Intel for the purpose of benchmarking NAS devices (Define: Network Attached Storage).  I’ve been looking for a solution to benchmark the new RAID-5 array I created on my Windows Server 2008 server (I love the RAID’s redundancy, but the write speeds are quite low).  I wanted to get a better idea of its performance, as Windows will report 250 – 150 MB READS and 20 – 50 MB WRITES, which is considerably poor considering the 4 drives are individually benchmarked at ~100 MB READS and 60 MB WRITES (They are Western Digital Caviar Blues / RE3 / RE16).

The software can be found here or from Intel here.

System Specifications:

Operating System: Microsoft Windows 2008 Enterprise Edition, SP1
CPU Type: Pentium 4 630, 3000 MHz w/ Hyperthreading
Motherboard Name: Dell Dimension 8400
Motherboard Chipset: Intel Alderwood i925XE
Motherboard Frontside Bus Speed: 800 MHz
System Memory (RAM): 4 GB, Dual Channel
System Memory Speed / Timings: DDR2-533 (266 MHz) / 4-4-4-12
Hard Drive Controller Interface: SATA I (1.5 Gbits / s) = 150 MB/s (maximum)
Hard Drives: Western Digital

• Drive #1 – WDC WD5002ABYS-01B1B (465 GB)
• Drive #2 – WDC WD5002ABYS-01B1B (465 GB)
• Drive #3 – WDC WD5000AAKS-00A7B (465 GB)
• Drive #4 – WDC WD5000AAKS-00A7B (465 GB)
• Drive #5 – WDC WD800BB-00JHC0 (74 GB) – SYSTEM

Raid Configuration: Software 4 disk RAID-5 (4 x 500GB, 1.36 TB Effective Storage Space)

System Memory Benchmark: Copy – 4790 MB/s, Read – 6266 MB/s, Write – 3341 MB/s, Latency – 92.7 ns
System Processor Benchmark: CPU ZLib – 10592 KB/s, CPU AES  – 3055

Benchmarks completed using Everest Ultimate Edition v4.20.1257

All drives are SATA II (3.0 GB/s) but are running in backwards-capability mode.

The primary roles of the server is to serve files and store backups (File Server) and web and application development and website hosting (Web Server).  I do not stream media, play music from the server or write extremely large amounts of data that are time sensitive.  Therefore, my decision for RAID-5 was based on the space savings (n – 1) storage availability and the redundancy by means of the parity.  I am willing to give up performance (write and read) for storage space and redundancy, but I want to know how much I’m actually giving up.

Tests

• HD Video Playback, 2x HD Video Playback, 3x HD Video Playback, 4x HD Video Playback

These benchmarks examine the behavior of the NAS unit while (simultaneously) playing one or more HD video files at 720p using Windows Media Player. Intel gives a percentage rate for the sequential reading of data in these tests, which lies at 99.5% for the HD Video Playback Test. With 2x HD Video Playback, it lies at 18.1%. The result is 6.6% with 3x HD Video Playback and 9.6 % with 4x HD Video Playback.

• HD Video Record

This test writes an HD Video file in 720p format to the NAS unit. This test is made of up of mostly sequentially transferred data.

• HD Video Playback & Recording

HD Video Play & Record examines the behavior of the NAS unit when simultaneously reading and writing an HD Video file in the 720p format. The sequentially-transferred data in this test is approximately 18% of the test.

• HD 2x Playback 2x Record

This benchmark is similar to the one above, but the proportion of sequential file operations is 3%.

• HD Playback With Office

This metric measures the data transfer rates when an HD Video file is read from the NAS unit while working with the Office applications. This test is made up of 608 files. The proportion of sequential file operations is 53.2%.

• HD Playback With Backup

Like the previous test, but this time an HD Video file is played while simultaneously carrying out a backup on the NAS unit.

• Content Creation

This benchmark is made up of 95% write operations to the NAS unit. This simulates the creation of files on the NAS unit such as is the case when, for example, using video editing programs.

• File Copy To NAS / File Copy From NAS

These tests determine the data transfer rate when copying files to or from the NAS unit. In both of these test processes, a 4 GB file is copied. Unlike with Backup / Restore, 64 KB is read and written.

• Directory Copy From NAS / Directory Copy To NAS

Similar to the previous test, files are copied to and from the NAS unit. A total of 126 files with a total size of approximately 188 MB are written and read across the network.

• Photo Album

This test determines how the NAS unit handles the supply of a multitude of small files—for example, viewing digital photographs stored on the NAS unit. It simulates the viewing of a total of 169 photographs with an overall size of approximately 1.2 GB.

Considerations and Assumptions

These tests were conducted on the Server, not over the network, which will probably result in very high throughput.  I did this to get a feel for the actual performance, not that felt over the wire, and because I’m currently running 100 Mbps (Cat 5e) on my LAN, not gigabit.  Thus, I did not want the network to be the bottleneck in these tests, as it would be saturated and skew the results.

I ran the tests 6 times, in each, manipulating the environment to establish a real world benchmark.  Since this benchmark is done via an application, it will compete with other processes for resources.  Additionally, it will compete with the actual Operating System who is responsible for transfering the data to the disk and calculating the parity for the raid (which is quite memory and CPU intensive).  For test 6 I ran the system in Safe Mode, utilizing only necessary processes and services to run the operating system (Safe Mode without Networking).  Thus, the numbers are quite high.  In the others, I ran Outlook, SQL, browsed the internet and downloading files via torrents (to the actual RAID, so this will mess with the numbers as well) – not all at the same time, of course, except for test 4.

Results

Test	1	2	3	4	5	6	Avg MB/s
HDVideo_1Play	267.789	267.789	80.364	54.54	59.134	274.603	167.37
HDVideo_2Play	223.736	223.736	68.638	44.619	75.123	223.204	143.18
HDVideo_4Play	177.201	177.201	70.222	54.731	73.009	180.005	122.06
HDVideo_1Record	626.098	626.098	651.41	618.888	678.788	732.636	655.65
HDVideo_1Play_1Record	82.744	82.744	85.224	71.802	79.058	155.986	92.93
ContentCreation	6.199	6.199	5.983	5.628	6.141	6.022	6.03
OfficeProductivity	25.383	25.383	25.474	20.958	26.249	27.955	25.23
FileCopyToNAS	633.475	633.475	748.91	690.827	768.598	806.578	713.64
FileCopyFromNAS	147.096	147.096	79.675	57.42	80.561	151.573	110.57
DirectoryCopyToNAS	65.156	65.156	25.13	18.384	23.418	81.739	46.50
DirectoryCopyFromNAS	44.048	44.048	20.412	15.53	20.929	47.274	32.04
PhotoAlbum	27.748	27.748	26.411	19.508	28.171	29.204	26.47

Discussion

I attribute the absurd file copy speeds to caching and buffering at both the OS, RAID and the Drive level, as well as the writes for the video recording.  All in all, I’m pleased with the benchmarks and am satisfied with the set up.  One thing to note is that the tests were done from the SYSTEM drive to the RAID, and thus, the SYSTEM drive introduced an additional bottleneck as the transfers from it to the RAID were going to be quite slow (the drive is benchmarked at ~56MB READ and ~30 WRITE).