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Benchmark Results: I/O Performance And Access Time

3.5'' Vs. 2.5'' SAS HDDs: In Storage, Size Matters
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The differences in database I/O performance aren’t huge, but they are noticable. The 2.5” drive does well here.

File server performance isn’t the Ultrastar C15K147's strong suit. The two 3.5” drives deliver better performance in this test.

We found similar results for the Web server test.

Lastly, the workstation test pattern confirms that the 3.5” drives are superior in I/O performance when relying on an individual drive. However, space and power consumption savings enable administrators to operate twice as many 2.5” drives as 3.5” options. In such configurations, the 2.5” array will always outperform 3.5” setups on performance, capacity, and efficiency. Cost might be an issue, but you can always look for the best price/capacity/performance sweet spot.

Access Time

Access times are slightly longer on the 2.5” drive.

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  • -2 Hide
    steddy , May 8, 2010 3:44 PM
    If the 3.5 inch drives have twice the number of platters as the 2.5 inch drives, shouldn't their performance be similar to that of two 2.5 inch drives in RAID? Or does the performance of multiple platters not scale that way?
  • -1 Hide
    Anonymous , May 8, 2010 11:31 PM
    Nice article.

    "Two 2.5” SAS drives in RAID will outperform one fast 3.5” SAS drive in every workload."

    I would like to see proof of this, as I don't believe the "in every workload" bit. RAID-0 and -5 don't always deliver performance as promised. As far as I know, it depends on the file sizes, among other factors. Applications that use thousands of little files (web servers come to mind) can't always get a good performance boost from data striping, as the overhead required to read/write many small files outweighs the speed gains achieved by spreading the load across multiple drives. In this case, one faster 3.5" drive might outperform two slower 2.5" drives.
  • 1 Hide
    Alvin Smith , May 9, 2010 2:56 AM

    SO ... We ALL DO have 5.25" drive bays as a common option ... Can you guess what I am gonna say next ??

    Perhaps mechanical drive manufactureres should revisit the 5.25" form-factor for super-perpendicular, ultra-dense, high-performance desktop apps, such as video editing and graphics (and other HD+ media content apps).

    UltraRaptor 5"x10K dual-platter short-stroked.

    = or not =
  • -1 Hide
    paperfox , May 10, 2010 5:07 AM
    lol, Alvin you beat me to it
    Ive always wondered what if the latest hard drive technology was applied to the old 5.25 standard. I can easily see 300 MB/s transfer speeds and at least 1 TB platters with enough room for maybe 6 or so in one drive. Although realistically the price per gigabyte would be unmatched and the price per performance and efficiency would be hideously low compared to the trend I see on page 8... unless you add another actuator arm :)  but thats a whole other article.
  • 0 Hide
    distortion , May 11, 2010 12:33 AM
    try spinning a stack of 5.25" disks at 10k rpm.
  • 1 Hide
    davidb77380 , May 12, 2010 2:08 PM
    "2.5” and 3.5” enterprise drives are based on the same platter diameter"
    LMAO ...another drive "expert" who doesn't know ____ from shinola.
  • 1 Hide
    GullLars , May 16, 2010 11:15 AM
    @Alvin Smith: I'm more interrested in high-density low-RPM 5,25" drives for desktops and fileservers. I would easily buy sine 10TB 5,25" 3600RPM (or 1800RPM?) drives for RAID-5 to store huge ammounts of media and other files. Given the price pr GB was right ofc. 50MB/s sequential read/write pr drive would be sufficient for mass storage.
  • 0 Hide
    Anonymous , June 4, 2010 12:11 PM
    " Two 2.5” SAS drives in RAID will outperform one fast 3.5” SAS drive in every workload"

    ...and what about a drive failure in your striped array? You should consider the whole, bigger picture, not just speed and capacity.
  • 0 Hide
    sohelm , April 6, 2013 10:38 PM
    WHICH ONE IS BATTER 2.5” SAS OR 3.5” SAS