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HP's $1,000 Smart Array P822 controller is outclassed by an on-board raid controller. I'm having a hell of a time trying to figure this one out. My problem is that performance on the HP controller is significantly below what the drive is capable of, as demonstrated on the Dell computer and other benchmarks performed by others online. I realize that these are 3rd party drives being used in an HP server, however, I still expect performance to be comparable and not be different by a 50x factor. If I went out and purchased a HP SSD, what performance should I expect to see? Please advise on anything that you believe would be likely to cause this problem, general recommendations or any reasons why my expectations should be adjusted.

Please see the image here: Image Link

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I have enabled "Physical Drive Write Cache State" on the controller and that helped a bit. The 4k reads and writes are still lacking. Any ideas? Here is a picture of the performance after the change. enter image description here

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  • can you take my question off hold?
    – DrWhy
    Apr 15, 2015 at 19:25
  • @joeqwerty can you please take this question off hold?
    – DrWhy
    Apr 16, 2015 at 16:36

1 Answer 1

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You're not one for the scientific method, are you?

  • Different operating systems.
  • Different platform (server versus workstation).
  • Different CPU architecture.
  • Unsupported SSD on the RAID controller.
  • Raw SATA versus a disk connected to a RAID controller backplane.
  • The assumption that a RAID controller is supposed to be "faster".
  • Misconfigured settings on the server's storage array.
  • What were the controller and logical drive cache settings?
  • Did you try without SmartPath enabled?

What type of result were you expecting?

What were you trying to compare?

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  • I reject that hypotheses. Of course I am. :). To answer your questions, I'm expecting the performance of the drive on the HP to be comparable to the performance of the same drive on the Dell. Thanks for listing out some general causes. My biggest concern is that this is caused because I'm using an unsupported SSD. Should I expect that the SSD performance when using an HP SSD would be be comparable to the current performance of the Dell?
    – DrWhy
    Apr 15, 2015 at 19:02
  • @DrWhy The performance of the SSD shouldn't be impacted by the use of the RAID controller. Did you try without SmartPath? What were the controller and logical drive cache settings? If you only care about using a single disk, use a dedicated HBA and skip the RAID controller.
    – ewwhite
    Apr 15, 2015 at 19:11
  • I've tried smart path both enabled and disabled. There was not any notable difference. When I disabled smart path, I left caching disabled.
    – DrWhy
    Apr 15, 2015 at 19:16
  • when smartpath was disabled and caching was enabled at 100% write, I got much better results, however, I determined that this is just the cache talking here and is not indicative of sustained and actual performance of the drive.
    – DrWhy
    Apr 15, 2015 at 19:18
  • I want to avoid this becoming an X-Y question. What is your intended goal? If it's to fill an HP server with consumer SSDs, I'd say it was not a good idea. If it's to run a single SSD, the configuration you have isn't quite right. Use an HBA. If it's academic, and you're just curious about the disparity, there are a lot of reasons this may be the case.
    – ewwhite
    Apr 15, 2015 at 19:19

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