Door Femme Taken

Architect

Influence of PCI speed on RAID performance examined

Server performance

To accurately show the performance differences we did not use Intel's IOMeter, instead we created some new server-benchmarks using the trace/playback method of Intel's IPEAK Storage Performance Toolkit. The access patterns created by IOMeter miss a sense of locality. Whilst in real life related data is often localized close to each other IOMeter creates access patterns that are always completely random. An example of locality to a high degree can be found in the form of a log file. The end of the log file will be on a fixed position on the disk which will move somewhat, but will not be placed randomly on the disk. Disk activity created by writing data to one or more log files can efficiently be optimized by a RAID-controller. This is not the case with the random patterns created by IOMeter.

The server benchmarks are based on a trace of disk-activity created by Apache2-webserver and a MySQL 4.0 database using Windows XP. The reason for using Windows is simple: Intel's IPEAK SPT does not work under non-Windows OS. The used machine was equipped with 2 AMD Opteron 242-processors and 2GB of RAM to ensure that optimizations by the OS's disk-cache had a realistic influence on disk activity. Using Apache bench Apache was ordered to serve pictures from the pics-archive of Tweakers.net which where stored five-fold to get a data-range of 2.5GB. Aside to serving pictures Apache was sent out to write some access, error and user agent logs also. The OS was given some time to fill its disk-cache to about 1.6GB before testing was started. Two types of the same test where made; a light flavor with a concurrency of 2 and a heavy flavor with a concurrency of 20 simultaneous requests. The differences in the trace can be seen; an average queue-length of 1.86 I/O's in the light test and 3.50 in the heavy test. The relation between the written and read amount of data is respectively 75/25 and 86/14. The transfer rate during the trace was 3.3MB/s on average during the light test and 35.1MB/s on average during the heavy test. Processor-load was under 100 percent in both cases which means the bottleneck here is the Mylex AcceleRAID 600 using four Atlas 15K in RAID 10.

The benchmark has a remarkable outcome; the differences between PCI-speed are very small. Even 32-bits 33MHz PCI performs almost as well as 64-bits 66MHz does under load on the MSI MegaRAID Elite 1600. The Mylex AcceleRAID 600 performs the same on both 66MHz and 100MHz PCI-X.

Tweakers.net StorageMark 2004 - Webserver Light (IOps)
Mylex AcceleRAID 600PCI-X 100 435
Mylex AcceleRAID 600PCI64/66 435
LSI MegaRAID Elite 1600PCI64/66 418
LSI MegaRAID Elite 1600PCI32/33 413
LSI MegaRAID Elite 1600PCI32/33Load 407
Tweakers.net StorageMark 2004 - Webserver Heavy (IOps)
LSI MegaRAID Elite 1600PCI64/66 568
LSI MegaRAID Elite 1600PCI32/33 562
LSI MegaRAID Elite 1600PCI32/33Load 556
Mylex AcceleRAID 600PCI-X 100 510
Mylex AcceleRAID 600PCI64/66 510

The database benchmark was made using a local copy of the Tweakers.net database. Via Apache bench a PHP-script was run, in it's turn opening random front-page, news, pricewatch and assorted using fopen(). The resulting SQL-queries made for a realistic load of the database server. During testing all logging by Apache was stopped to ensure only MySQL and Windows where accessing the hard disk. Like before we made a light and a heavy benchmark. In the light test the concurrency level in Apache bench was 10 and in the heavy test made up for 50 simultaneous requests. During this the number of queries on the database server rose to about 500 p/s which can be compared to Tweakers.net during rush-hour.

The Mylex AcceleRAID 600 and the MSI MegaRAID Elite 1600 performed completely opposite in this test. The MegaRAID is faster under a light load while the AcceleRAID takes the lead when there is a heavy load. Differences between 64-bits 66MHz and 32-bits 33MHz PCI are much bigger than in the webserver benchmarks. The MegaRAID performs 12 to 16 percent better when placed on the faster bus. When the legacy PCI-bus receives additional load the difference rises to 22 to 30 percent. In the light db-server benchmark the AcceleRAID performs the same on both the 66MHz and the 100MHz PCI-X bus, the heavy benchmarks shows an increase in speed of about 2 percent when using the 100MHz bus.

Tweakers.net StorageMark 2004 - Database server Light (IOps)
LSI MegaRAID Elite 1600PCI64/66 1316
LSI MegaRAID Elite 1600PCI32/33 1176
LSI MegaRAID Elite 1600PCI32/33Load 1075
Mylex AcceleRAID 600PCI-X 100 990
Mylex AcceleRAID 600PCI64/66 990
Tweakers.net StorageMark 2004 - Database server Heavy (IOps)
Mylex AcceleRAID 600PCI-X 100 1724
Mylex AcceleRAID 600PCI64/66 1695
LSI MegaRAID Elite 1600PCI64/66 1639
LSI MegaRAID Elite 1600PCI32/33 1408
LSI MegaRAID Elite 1600PCI32/33Load 1250

It's fair to assume that differences between legacy PCI and 64-bits 66MHz PCI-X would be even greater when the benches where unleashed on a RAID-0 array using four Atlas 15K's. Since no sober systems-engineer would trust his sensitive data to a RAID-0 array we performed the benchmarks on a RAID-5 array with four disks.


Nintendo Switch (OLED model) Apple iPhone SE (2022) LG G1 Google Pixel 6 Call of Duty: Vanguard Samsung Galaxy S22 Garmin fēnix 7 Nintendo Switch Lite

Tweakers vormt samen met Hardware Info, AutoTrack, Gaspedaal.nl, Nationale Vacaturebank, Intermediair en Independer DPG Online Services B.V.
Alle rechten voorbehouden © 1998 - 2022 Hosting door True

Tweakers maakt gebruik van cookies

Tweakers plaatst functionele en analytische cookies voor het functioneren van de website en het verbeteren van de website-ervaring. Deze cookies zijn noodzakelijk. Om op Tweakers relevantere advertenties te tonen en om ingesloten content van derden te tonen (bijvoorbeeld video's), vragen we je toestemming. Via ingesloten content kunnen derde partijen diensten leveren en verbeteren, bezoekersstatistieken bijhouden, gepersonaliseerde content tonen, gerichte advertenties tonen en gebruikersprofielen opbouwen. Hiervoor worden apparaatgegevens, IP-adres, geolocatie en surfgedrag vastgelegd.

Meer informatie vind je in ons cookiebeleid.

Sluiten

Toestemming beheren

Hieronder kun je per doeleinde of partij toestemming geven of intrekken. Meer informatie vind je in ons cookiebeleid.

Functioneel en analytisch

Deze cookies zijn noodzakelijk voor het functioneren van de website en het verbeteren van de website-ervaring. Klik op het informatie-icoon voor meer informatie. Meer details

janee

    Relevantere advertenties

    Dit beperkt het aantal keer dat dezelfde advertentie getoond wordt (frequency capping) en maakt het mogelijk om binnen Tweakers contextuele advertenties te tonen op basis van pagina's die je hebt bezocht. Meer details

    Tweakers genereert een willekeurige unieke code als identifier. Deze data wordt niet gedeeld met adverteerders of andere derde partijen en je kunt niet buiten Tweakers gevolgd worden. Indien je bent ingelogd, wordt deze identifier gekoppeld aan je account. Indien je niet bent ingelogd, wordt deze identifier gekoppeld aan je sessie die maximaal 4 maanden actief blijft. Je kunt deze toestemming te allen tijde intrekken.

    Ingesloten content van derden

    Deze cookies kunnen door derde partijen geplaatst worden via ingesloten content. Klik op het informatie-icoon voor meer informatie over de verwerkingsdoeleinden. Meer details

    janee