Rich Mingin (PLUG) via plug on 3 Jan 2022 07:39:07 -0800

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Re: [PLUG] Moving mdadm RAID-5 to a new PC

Pis are wonderful for a lot of things, but I/O is *not* one of them. I can almost guarantee that any RAID-5 on a Pi, unless it's backended on 3.5" floppy drives, is going to be severely bottlenecked. When I test I/O throughput on my Pis, best case is usually around 100MB/s or so, and for something like a USB-based RAID5, you're cutting that 3 or 4 ways, maybe more. The USB controller on the Pis serves *many* masters. I think the ethernet controller is still on it, for example.

So depending on what you're doing, the answer changes. If it's a NAS, get an old netbook and you'd have better performance, or repurpose an old desktop for another order of magnitude again. If it's just a toy for projects and learning, go to a simple mirror and things will be a lot more performant (mirror doesn't need the CPU doing XOR, and only generates two reads/writes per I/O instead of potentially 4+).

More info will yield better answers. Good luck.

On Mon, Jan 3, 2022 at 10:31 AM Adam Zion via plug <> wrote:
Long story short: I have recently set up a home NAS on a Raspberry Pi 2 via mdadm. It works splendidly, if slowly. Hence wondering if it'd make sense to migrate it to a faster Pi. Has anyone done this before? Or would I be better off leaving the RAID where it is and moving all other services- like the streaming media server or Pi-hole ad blocker- onto another host?


Adam+Zion, MSIS
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