Multiple USB disks to RPI - A power problem?

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    • hekmatk wrote:

      If I had an SSD, this is where I should point my database in order to have ultimate performance, right?
      Not sure if it has an singnificant impact on performance when using Plex. I put also my database on an SSD, but the reason was to avoid spin up of the data drives.
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    • macom wrote:

      hekmatk wrote:

      If I had an SSD, this is where I should point my database in order to have ultimate performance, right?
      Not sure if it has an singnificant impact on performance when using Plex. I put also my database on an SSD, but the reason was to avoid spin up of the data drives.
      I do think an SSD would improve performance. For instance when I'm scrolling down my plex library, I have to stop scrolling and wait for ~1second before the posters of the movies load. I'm currently using a regular HDD. I'm hoping that by switching to SSD, I will not have to wait this 1second every time I scroll (yes, yes, my time is that valuable :P ). But in all seriousness, I do think an SSD for the database will be a big improvement.

      What is debatable is either the drive running OMV and the plex plugin should be SSD or just HDD. But given it will be of a small size, I would just get a small size ssd to decrease the spinning noises.
    • Nibb31 wrote:

      An SSD connected over USB will not do anything for performance on a Raspberry because the bottleneck is on the USB bus, not the drive throughput. Even the slowest HDDs will easily saturate the shared USB bus.

      It's not always about bandwidth (sequential performance) but often more or only about random IO performance. There SSDs always outperform any HDD since they show much higher random IO performance and stuff like USB2 bandwidth limitation do not matter (that much).

      See here please the Pine64 results made on an USB2 port: forum.armbian.com/topic/1925-s…findComment&comment=51350

      A fast SSD even on an USB2 port achieves 2,000 random IOPS with 4K block size while even fast HDDs stay well below 200 IOPS. So even on an Raspberry Pi (which has the slowest USB2 implementation of all SBC out there since all drives behind a hub and not UAS capable) any SSD will show magnitudes higher random IO scores than any HDD even if a slow USB2 interface bottlenecks sequential performance to a tenth or below.
    • Nibb31 wrote:

      An SSD connected over USB will not do anything for performance on a Raspberry because the bottleneck is on the USB bus, not the drive throughput. Even the slowest HDDs will easily saturate the shared USB bus.

      tkaiser wrote:

      Nibb31 wrote:

      An SSD connected over USB will not do anything for performance on a Raspberry because the bottleneck is on the USB bus, not the drive throughput. Even the slowest HDDs will easily saturate the shared USB bus.
      It's not always about bandwidth (sequential performance) but often more or only about random IO performance. There SSDs always outperform any HDD since they show much higher random IO performance and stuff like USB2 bandwidth limitation do not matter (that much).

      See here please the Pine64 results made on an USB2 port: forum.armbian.com/topic/1925-s…findComment&comment=51350

      A fast SSD even on an USB2 port achieves 2,000 random IOPS with 4K block size while even fast HDDs stay well below 200 IOPS. So even on an Raspberry Pi (which has the slowest USB2 implementation of all SBC out there since all drives behind a hub and not UAS capable) any SSD will show magnitudes higher random IO scores than any HDD even if a slow USB2 interface bottlenecks sequential performance to a tenth or below.
      I guess SSD will always be better then. But for clarification, I am currently planing to move away from rpi and move to a PC-NAS aka the SSD will be linked to a motherboard rather than USB (didn't precise it in this specific post... was talking about it in some other post).
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