Benchmarks from the IPEAK Storage Performance Toolkit offer a clear view on the effects of striping on I/O performance with desktop workloads. Keep in mind though that we are talking about I/O performance here, which does not necessarily result in better overall performance. When the computer cannot process the I/O data fast enough because other parts, like for instance the CPU, form a bottleneck, the result will be a system that does not work one single bit faster than before. To visualize some examples of the time than can be saved by implementing RAID 0, we tested several configurations by performing some normal Windows-actions and measuring the time necessary to perform those actions with a stopwatch. Every test was performed three times to get more reliable results and before performing each test, Windows was rebooted. The complete installation of the operating system, including all applications and data files was transferred from a Ghost image to the hard drives and the RAID arrays.
The different tests vary from booting up Windows and opening pictures in Photoshop, to copying files and installing a service pack. Some tests were performed with some extra background activity like a backup, virus scan or file copy. Those are some typical situations where there's a big load on the hard drives, while users still want to work with maximum speed.
On the starting grid we see two Raptor WD360GD's, two Raptor WD740GD's, a MegaRAID SCSI 320-2X 512MB with four Atlas 15K's in a RAID 5 configuration and some single drive configs with the Raptors mentioned earlier. The computer was provided with a dual Athlon XP 2400+ on an Asus A7M266-D-motherboard with 1GB PC2100 ECC Registered DDR SDRAM and a GeForce FX 5900. Performance of this system is comparable to an Athlon 64 2800+. All SATA-disks were tested on a FastTrak S150 TX2plus, which was placed on a 66MHz PCI-slot. Attempts to get the 3ware Escalade 9500S-8 in this tests failed because it refused to enable write-back caching on the hard drives. This resulted in a poor score in the Photoshop test. Apart from single and two-drive RAID 0 configurations with Raptor WD740GD disks, we also tested a setup with two independent Raptors. The Windows pagefile, Photoshop scratch disk and temporary directories were stored on the second disk. The setup with independent disks performed an alternative for the filecopy benchmark where files were copied from the first disk to the second, instead of copying to the same disk. Not completely fair, but it does give us an idea about how independent disks perform in such situations.
Everyone who has ever worked with Photoshop before will know its freaky need for memory. It doesn't matter whether you have 512MB, 1GB or 2GB of memory, Photoshop can and will use it all. Apart from that, there are scratch files that weigh over 100MB, if not GB. This results in rather heavy loads on the hard drive. Therefore, our first test consists of opening several pictures in Photoshop CS. We are talking about 25 JPEG's with a resolution of eight megapixel and an average filesize of 4.76MB. Uncompressed, such a file takes 22.9MB of data. Somewhere halfway opening the pictures, we notice the scratchfile to start suffering to finish on a size of almost 1GB.
Loading times of the different drive and RAID configurations don't show any remarkable differences. Opening pictures seems to put more load on the CPU, and not as much on the hard drive. The MegaRAID SCSI 320-2X finishes first, 16 percent better than the last one in the row, the single Raptor WD360GD. Creating a dedicated swap and scratch partition seems to offer a bit of advantage, but results in less improvement than striping two disks.
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| Atlas 15K | | 4 | | RAID 5 | | MegaRAID SCSI 320-2X | |    38,4 | |
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| Raptor WD740GD | | 2 | | RAID 0 | | FastTrak S150 TX2plus | |    39,4 | |
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| Raptor WD360GD | | 2 | | RAID 0 | | FastTrak S150 TX2plus | |    39,6 | |
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| Raptor WD740GD | | 2 | | Dual | | FastTrak S150 TX2plus | | 43,0 | |
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| Raptor WD740GD | | 1 | | Single | | FastTrak S150 TX2plus | | 44,1 | |
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| Raptor WD360GD | | 1 | | Single | | FastTrak S150 TX2plus | | 45,9 | |
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Making regular backups is a good idea, certainly when storing valuable data on a RAID 0 array (which is not such a good idea, by the way). Therefore we performed the same test again, but this time using Windows XP's default backup tool to back up 10GB of pictures to a network drive, using an Intel Pro/1000MT gigabit Ethernet controller on the client, and a Broadcom NeXtreme PCI-X gigabit Ethernet controller in the server, linked together through a Micronet switch with eight ports.
The Raptor WD360GD seems to suffer a bit from the simultaneous activities performed by Photoshop and the backup. This problem seems to be solved with the WD740GD though, probably because of the improved caching. The gold medal goes to the MegaRAID SCSI 320-2X again, who doesn't seem to have a problem with the backup, since the necessary time for opening those pictures only rises with 20 percent. The Raptor WD740GD needs 50.6 percent more time in single configuration and 23.6 percent extra time when configured with two drives in RAID 0. Using RAID 0 on the Raptor WD360GD offers us 36.9 percent of performance gain. RAID 0 with the Raptor WD740GD results in 11.6 percent improvement and even 26.7 percent when using a dedicated disk for scratch and swap files. This configuration performs very good in our test.
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| Atlas 15K | | 4 | | RAID 5 | | MegaRAID SCSI 320-2X | | 46,0 | |
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| Raptor WD740GD | | 2 | | Dual | | FastTrak S150 TX2plus | | 48,7 | |
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| Raptor WD740GD | | 2 | | RAID 0 | | FastTrak S150 TX2plus | | 58,7 | |
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| Raptor WD740GD | | 1 | | Single | | FastTrak S150 TX2plus | | 66,4 | |
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| Raptor WD360GD | | 2 | | RAID 0 | | FastTrak S150 TX2plus | | 70,8 | |
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| Raptor WD360GD | | 1 | | Single | | FastTrak S150 TX2plus | | 112,3 | |
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In our next benchmark, we are searching a Thunderbird mailbox for the word 'Pentium'. This mailbox is over 600MB in size and the search seems to put a decent load on the drive, but on second thought, disk load is not heavy enough to get reliable results. There is not much to discuss therefore: this test is almost completely limited by cpu performance. Running a virus scan in the background does raise the search times a little but there is no obvious difference in performance between the different configurations.
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| Atlas 15K | | 4 | | RAID 5 | | MegaRAID SCSI 320-2X | | 35,6 | |
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| Raptor WD360GD | | 2 | | RAID 0 | | FastTrak S150 TX2plus | | 35,8 | |
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| Raptor WD740GD | | 2 | | RAID 0 | | FastTrak S150 TX2plus | | 35,9 | |
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| Raptor WD740GD | | 2 | | Dual | | FastTrak S150 TX2plus | | 36,1 | |
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| Raptor WD740GD | | 1 | | Single | | FastTrak S150 TX2plus | | 36,1 | |
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| Raptor WD360GD | | 1 | | Single | | FastTrak S150 TX2plus | | 36,1 | |
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| Atlas 15K | | 4 | | RAID 5 | | MegaRAID SCSI 320-2X | | 40,4 | |
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| Raptor WD360GD | | 2 | | RAID 0 | | FastTrak S150 TX2plus | | 41,3 | |
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| Raptor WD740GD | | 1 | | Single | | FastTrak S150 TX2plus | | 41,6 | |
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| Raptor WD740GD | | 2 | | RAID 0 | | FastTrak S150 TX2plus | | 42,4 | |
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| Raptor WD740GD | | 2 | | Dual | | FastTrak S150 TX2plus | | 42,4 | |
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| Raptor WD360GD | | 1 | | Single | | FastTrak S150 TX2plus | | 42,9 | |
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