Request Advice: How to power 4 SSDs connected to RPI

Heisen said:
No its not USB2, it becomes what the device uses. Think of it like a USB pass through device. It doesn’t matter if the connection is USB3 or USB2 , because both those use the same 4 wire protocol. Just like a USB cable. There are no specific USB2 or USB3 cables.
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?? As per my understanding, USB3 and above require 9 pins, including the vbus. With 4 pins you can only do up to usb2, 480 megabits/sec
 
ze_cook said:
?? As per my understanding, USB3 and above require 9 pins, including the vbus. With 4 pins you can only do up to usb2, 480 megabits/sec
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OP has Pi 3b+, which doesn't have USB3 ports.

That said, if anyone was building a custom board like this, it would be nice to have some future proofing since USB3 is anyway backwards compatible.
 
gourav said:
OP has Pi 3b+, which doesn't have USB3 ports.

That said, if anyone was building a custom board like this, it would be nice to have some future proofing since USB3 is anyway backwards compatible.
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Ah, in that case this board won't cause any further bottleneck. But, to reiterate, what @Heisen has developed is a USB2 power injector, and won't do anything over USB2.

Using a pi 3b+ as a nas is a terrible idea, because
a. The usb ports are usb 2, crippling your ssd bandwidth. Even if that's not a concern,
b. Even the ethernet port is connected over USB2 internally, max transfers in and out of that nic is going to be ~300mbps realistically

If possible, please upgrade to rpi 4. It has 2x usb3, so even with a usb hub, splitting the bandwidth 4 ways you get 1.25gbps each port. Also, the ethernet is true gigabit connected over pcie, not USB.
 
ze_cook said:
USB3 and above require 9 pins, including the vbus. With 4 pins you can only do up to usb2, 480 megabits/sec
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Yes, you are correct that USB3 has 9 pins, I had a brain fart there. My apologies.

ze_cook said:
But, to reiterate, what @Heisen has developed is a USB2 power injector, and won't do anything over USB2.
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Yet, time make it usb3.

gourav said:
it would be nice to have some future proofing since USB3 is anyway backwards compatible.
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As I read the USB3, USB3.1 and USB3.2 use the same 9 pin connection, so if usb3 connector is used, it will be forward compatible as well.
 
Actually whatever I can. I want to keep copies of important documents in this. I do expect to at least have about 100 Mbps for delta updates from the laptop now that I have backed up the base set.

Again I am not expecting performance but reliability from the file system on the drives. I can live with hardware failure but I must not lose data. Currently I am using a simple lvm mirror across two 120 GB drives & plan to add another volume of mirrored 480 GB drives.

This is my third copy of the data. Laptop, NAS & this.
 
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bornlibra23 said:
Actually whatever I can. I want to keep copies of important documents in this. I do expect to at least have about 100 Mbps for delta updates from the laptop now that I have backed up the base set.

Again I am not expecting performance but reliability from the file system on the drives. I can live with hardware failure but I must not lose data. Currently I am using a simple lvm mirror across two 120 GB drives & plan to add another volume of mirrored 480 GB drives.

This is my third copy of the data. Laptop, NAS & this.
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If what you're looking for is data consistency and backup, I'll really recommend you build a cheap nas but with PC hardware rather than using a RPI.
  • The RPI is just not powerful enough to power HDDs which you can easily do with a proper mobo.
  • The bus on RPI3 is shared b/w USB/Ethernet, so when doing something like a disk read, you'll effectively have half of the bandwidth available as half will be taken by data over USB. https://forums.raspberrypi.com/viewtopic.php?t=207940
  • For data consistency, you should consider using a ZFS filesystem across your storage. It has built in mechanisms for storage and timely detection/correction of errors.
  • Here's the network tests of different RPI models: https://notenoughtech.com/raspberry-pi/raspberry-pi-internet-speed/
  • You can see the bandwidth here for network-only communication, what you get will be effectively half of this.
A RPI3B was my first nas with a simple 320G hdd from a old pc. I learnt things the hard way and therefore moved to my old Intel DualCore which was then not powerful for serving/transcoding media.
The current NAS I have is built on i5-3470 with 4x2TB and performs well except for a few things.

let me know if you have any more questions...
 
demon_slayer said:
If what you're looking for is data consistency and backup, I'll really recommend you build a cheap nas but with PC hardware rather than using a RPI.
  • The RPI is just not powerful enough to power HDDs which you can easily do with a proper mobo.
  • The bus on RPI3 is shared b/w USB/Ethernet, so when doing something like a disk read, you'll effectively have half of the bandwidth available as half will be taken by data over USB. https://forums.raspberrypi.com/viewtopic.php?t=207940
  • For data consistency, you should consider using a ZFS filesystem across your storage. It has built in mechanisms for storage and timely detection/correction of errors.
  • Here's the network tests of different RPI models: https://notenoughtech.com/raspberry-pi/raspberry-pi-internet-speed/
  • You can see the bandwidth here for network-only communication, what you get will be effectively half of this.
A RPI3B was my first nas with a simple 320G hdd from a old pc. I learnt things the hard way and therefore moved to my old Intel DualCore which was then not powerful for serving/transcoding media.
The current NAS I have is built on i5-3470 with 4x2TB and performs well except for a few things.

let me know if you have any more questions...
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Second this advice. Used/refurbished tiny PCs pr NUCs also work great. And they'll have enough power to run 4 SSDs off USB.
 
USB3

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bornlibra23 said:
I think that will be fine.
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Okay will do, it will be able to provide 15watt of power, spread across 4 USB ports.

We are half way there in developing this niche product, now it has got my full interest, I will order the PCBs and slap on those components, when I get free time. I might be able to send you one in the future, but don't quote me on that. ;)
 
You can get powered usb hub.
It won't matter if you do it via 4 usb or 1 usb via hub. The speed will still be same as those port share same bandwidth.

Usb 3 will have 6gbps max. RPi have shared 4.8gbps pcie lane for all 4 ports.
 
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Heisen said:
Okay will do, it will be able to provide 15watt of power, spread across 4 USB ports.

We are half way there in developing this niche product, now it has got my full interest, I will order the PCBs and slap on those components, when I get free time. I might be able to send you one in the future, but don't quote me on that. ;)
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Hi were you able to make some progress on this? @Heisen
 
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