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Upgrade Raspberry Pi 4 with a NVMe boot drive

alexellisuk.medium.com

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Re: Upgrade Raspberry Pi 4 with a NVMe boot drive

#61

Post by kup0 »

The USB is limiting this so much there is no need to go with NVME over SATA, IMHO.

I see the USB3 result for the "M.2 SSD" (I assume the author means SATA?) being ~30/MB but almost surely something is going wrong there. That is not a normal result for any mid-to-high level SATA SSD. Plenty of SATA M.2 SSDs can easily hit the same speeds the NVME drive is hitting (specifically when on USB3). NVME might give you some additional random r/w performance, however.

It seems like overkill to use NVME on USB 3.0 when SATA can saturate that bus just as easily. SATA M.2 drives will also run cooler. Some NVME USB controllers are notoriously hot-running

Re: Upgrade Raspberry Pi 4 with a NVMe boot drive

#62

Post by emidln »

kup0 wrote: post #61

The USB is limiting this so much there is no need to go with NVME over SATA, IMHO. I see the USB3 result for the "M.2 SSD" (I assume the author means SATA?) being ~30/MB but almost surely something is going wrong there. That is not a normal result for any mid-to-high level SATA SSD. Plenty of SATA M.2 SSDs can easily hit the same speeds the NVME drive is hitting (specifically when on USB3). NVME might give you some a…

Power consumption would be my guess for why one would choose NVME over SATA in this application.

Re: Upgrade Raspberry Pi 4 with a NVMe boot drive

#64

Post by justin66 »

dheera wrote: post #43

Honestly I'd get rid of the USB and use the Pi 4 compute module with NVMe next year. USB connectors suck balls, one bump or connector dangling over the edge of your desk that gets hit by a hip and you have a device reenumeration, no idea what havoc that would have on the kernel that's running off it. USB is evil. Never use it for anything mission critical.

> one bump or connector dangling over the edge of your desk that gets hit by a hip and you have a device reenumeration

It’s fun to think about the horrors which might result with similar mistreatment of old school external SCSI hardware. USB is fine; use quality cables and don’t run your computer in a disco if you can help it.

Re: Upgrade Raspberry Pi 4 with a NVMe boot drive

#65

Post by kup0 »

emidln wrote: post #62
kup0 wrote: post #61

The USB is limiting this so much there is no need to go with NVME over SATA, IMHO. I see the USB3 result for the "M.2 SSD" (I assume the author means SATA?) being ~30/MB but almost surely something is going wrong there. That is not a normal result for any mid-to-high level SATA SSD. Plenty of SATA M.2 SSDs can easily hit the same speeds the NVME drive is hitting (specifically when on USB3). NVME might give you some a…

Power consumption would be my guess for why one would choose NVME over SATA in this application.

Hrm, maybe over USB it's different because of the performance limitations, but my understanding was that SATA was lower power draw.

Though maybe I'm wrong and/or potentially this differs on a per-drive/per-controller basis.

Re: Upgrade Raspberry Pi 4 with a NVMe boot drive

#66

Post by johnchristopher »

Depending on what you want to do you can get good results using tmpfs ram disk in combination with a non volatile USB plugged storage.

Eg: I convert some RTSP stream from a pi zero to HLS on a pi4 by ffmpegging the RTSP stream to HLS files in the RAM disk. I use bindfs to make this mountpoint available as a www-data folder in /home/pi/ssd/web/hls (which is actually on an USB plugged SSD) for HTML viewing in the browser. Motion triggers events, those events can be recorded from the RTSP stream or the ramdisk (holding HLS files) to the attached SSD. The HLS conversion adds a 30 second buffer so any triggers on the RTSP stream has an hls capture starting 30 seconds before the event and the SD card is never touched and I could use a spinning disk, it wouldn't be a bottleneck (but I am somehow more confident the SSD will be more stable power wise).

Re: Upgrade Raspberry Pi 4 with a NVMe boot drive

#67

Post by kelnos »

nominated1 wrote: post #6

These sorts of posts come up often and I cringe every time I see dongle attached storage. An unnecessary additional failure point seems counterproductive. I have a Raspberry Pi and I use an SD card because what I’m using it for doesn’t require anything more. If you need fast storage I believe you should buy an appropriate device and maybe petition the Foundation to add it in a future model. Right tool for the job and…

I disagree. The RPi is a pretty versatile little machine. Yes, it does have some limitations, and the workarounds for those (like NVMe-over-USB) are not particularly optimal, but by sticking with RPi (rather than one of the other myriad SBCs), you get consistency and a reasonable expectation that the board is still going to be supported with an up-to-date userland 10 years from now.

I've been wanting to build a 4-bay SBC NAS for years now, but I haven't been able to bring myself to trust the community and support for some of the other boards that do give you direct access to the PCIe bus so you can actually get decent performance.

Now I'm waiting for someone to come up with something based on the Compute Module 4... (There was a post about someone designing a PCB for something that would do the trick the other day, but it requires some 0.4mm pitch soldering skills that I just don't have the equipment for.)

Re: Upgrade Raspberry Pi 4 with a NVMe boot drive

#68

Post by geerlingguy »

Just wanted to note that you DO get a large (measurable) performance increase using NVMe natively via the Pi's PCIe bus vs. through a USB 3.0 adapter; see my notes in my Compute Module 4 review: https://www.jeffgeerling.com/blog/2020/raspberry-pi-compute-...

I should probably dedicate a post and video to NVMe support, but basically you get double the random IO numbers if using NVMe vs NVMe-via-USB3. You can't boot off internal NVMe though, at least not natively with no microSD card or eMMC volume.

Re: Upgrade Raspberry Pi 4 with a NVMe boot drive

#69

Post by kelnos »

FpUser wrote: post #60

One step in this description is not really needed. One can do diskdup from SD card to SSD right from inside the same Pi booted originally for SD card.

Usually not a great idea to make an image of a disk when filesystems on it are mounted writable.

Re: Upgrade Raspberry Pi 4 with a NVMe boot drive

#70

Post by 1vuio0pswjnm7 »

kzrdude wrote: post #23

One needs to login to read. I'm sorry, medium is not a very charitable blog host, and will cost the blog a large part of its audience with these new rules, unfortunately.

"One needs to login to read."

Not if Javascript is disabled. No need for cookies either.

Alternatively, blocking cdn.client.medium.com where the Javascript is sourced in Developer Tools or via ad blocker, /etc/hosts, DNS, etc. will work, too.

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