ryan810cows
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Joined: Mon Aug 26, 2019 11:41 pm

Max USB Drives

Mon Aug 26, 2019 11:55 pm

Hello Pi World!
I'm VERY new and am wanting to get into the world of PI!
I will be getting (2) PI4's soon.
(1) will be a RetroPi
(1) will be a Backup NAS to my FreeNAS server

Here comes the question.....

Specifically talking about the Backup NAS...
If I get this 7-port USB Hub (https://t.ly/y2xnD), will the PI4 be able to recognize all (7) ports *PLUS MORE*?
I will be using this HDD rack to hold (5) drives at first.. later I plan to add (5) more (https://t.ly/RpJZ3).
I will use this SATA to USB (https://t.ly/YdExJ) and I will power each HDD on the rack by a PC Power supply.

So.. what do you think? Keep in my, i don't care about x-fer speed, this is just a file storage backup that will run (1 to 2 times a week).

Your thoughts are MOST appreciated!

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topguy
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Location: Trondheim, Norway

Re: Max USB Drives

Wed Aug 28, 2019 12:12 pm

Max number of USB devices connected to any computer ( afaik ) is 127 but also counting all USB-hubs.

ryan810cows
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Joined: Mon Aug 26, 2019 11:41 pm

Re: Max USB Drives

Wed Aug 28, 2019 12:26 pm

THANK YOU!! :D Just what I needed to know!

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rpdom
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Re: Max USB Drives

Wed Aug 28, 2019 1:33 pm

topguy wrote:
Wed Aug 28, 2019 12:12 pm
Max number of USB devices connected to any computer ( afaik ) is 127 but also counting all USB-hubs.
The Pi 0-3 had a limit of something like 6 USB endpoints. The Pi 4B uses a different USB system and supports up to 32 devices (see here: https://www.raspberrypi.org/forums/view ... 5#p1484595)

ryan810cows
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Joined: Mon Aug 26, 2019 11:41 pm

Re: Max USB Drives

Wed Aug 28, 2019 1:40 pm

That will still work VERY well for my needs!
Thanks for the help guys!

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scruss
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Re: Max USB Drives

Wed Aug 28, 2019 1:51 pm

All the devices you list — well, the hub and the USB→SATA adapter — are USB 2. This negates any advantage of using a Raspberry Pi 4. I know you said you didn't care about speed, but your once or twice per week backup might still be backing up the next time you want to do it.
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ryan810cows
Posts: 6
Joined: Mon Aug 26, 2019 11:41 pm

Re: Max USB Drives

Wed Aug 28, 2019 2:15 pm

I have thought about that a good bit and for now i'm willing to take the chance.
By using the PI4 is sounds like i will get 32 devices instead of just 6 (if i understood that correctly b/t the 3 vs. 4) - so that's a big plus
I'm also hoping the increase in ram and processor speed will help any "computing" i may need later down the road.

But yes, it will still run at 2.0 and i'm hoping it will be fast enough for just a secondary backup.

Thank for the input though!

trejan
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Re: Max USB Drives

Wed Aug 28, 2019 2:38 pm

ryan810cows wrote:
Wed Aug 28, 2019 2:15 pm
By using the PI4 is sounds like i will get 32 devices instead of just 6
You'll be able to have a lot of HDs but IIRC USB hubs count towards the 32 devices. I'd be wary about going right up to the limits as well.

ryan810cows
Posts: 6
Joined: Mon Aug 26, 2019 11:41 pm

Re: Max USB Drives

Wed Aug 28, 2019 3:06 pm

Understood and I agree. Not pushing the limits.
I plan to have no more then (10) HDD's and (2) USB-7port Hubs = 12 connected devices.
I should be OK..... theoretically!! :shock:

dmikester1
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Re: Max USB Drives

Wed Aug 28, 2019 3:26 pm

Doesn't the Pi 4 have usb 3.0? Why wouldn't you get a 3.0 hub?

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FTrevorGowen
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Re: Max USB Drives

Wed Aug 28, 2019 3:27 pm

ryan810cows wrote:
Wed Aug 28, 2019 3:06 pm
Understood and I agree. Not pushing the limits.
I plan to have no more then (10) HDD's and (2) USB-7port Hubs = 12 connected devices.
I should be OK..... theoretically!! :shock:
However, IIRC, so-called "7-port hubs" are two 4-port hubs "in series" ie. hub1 port4 feeds/connects to the input of the second hub. Also, as far as USB-2 hubs are concerned, unless things have changed, be wary of (the cheap versions of) something like this:
http://www.cpmspectrepi.uk/raspberry_pi ... rtHub.html and the associated measurements here: http://www.cpmspectrepi.uk/raspberry_pi ... st_Results (or rather, any "included" PSU)
Trev.
Still running Raspbian Jessie on some older Pi's (an A, B1, B2, B+, P2B, 3xP0, P0W) but Stretch on my 2xP3A+, P3B+, P3B, B+, A+ and a B2. See: https://www.cpmspectrepi.uk/raspberry_pi/raspiidx.htm

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RaTTuS
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Re: Max USB Drives

Wed Aug 28, 2019 3:33 pm

ryan810cows wrote:
Wed Aug 28, 2019 3:06 pm
Understood and I agree. Not pushing the limits.
I plan to have no more then (10) HDD's and (2) USB-7port Hubs = 12 connected devices.
I should be OK..... theoretically!! :shock:
10 HD,
your pushing a lot of things here
you can get 14TB Drives , or 10TB or even 4TB -
6x 4TB is plenty for anything .... [ha]
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ryan810cows
Posts: 6
Joined: Mon Aug 26, 2019 11:41 pm

Re: Max USB Drives

Wed Aug 28, 2019 3:38 pm

Understood.
But i have FREE 500 gb HDD's from work b/c we change them out so often as a preventive measure and most of the time they are happy and healthy still.

That would be me at 5 tb of storage in total if i just use them as individual HDD's and not do any RAID.

drgeoff
Posts: 9803
Joined: Wed Jan 25, 2012 6:39 pm

Re: Max USB Drives

Wed Aug 28, 2019 3:44 pm

FTrevorGowen wrote:
Wed Aug 28, 2019 3:27 pm
ryan810cows wrote:
Wed Aug 28, 2019 3:06 pm
Understood and I agree. Not pushing the limits.
I plan to have no more then (10) HDD's and (2) USB-7port Hubs = 12 connected devices.
I should be OK..... theoretically!! :shock:
However, IIRC, so-called "7-port hubs" are two 4-port hubs "in series" ie. hub1 port4 feeds/connects to the input of the second hub. Also, as far as USB-2 hubs are concerned, unless things have changed, be wary of (the cheap versions of) something like this:
http://www.cpmspectrepi.uk/raspberry_pi ... rtHub.html and the associated measurements here: http://www.cpmspectrepi.uk/raspberry_pi ... st_Results (or rather, any "included" PSU)
Trev.
Indeed, I had one of those briefly in 2012 (when the original RPi was launched) but returned it because of the included PSU (UK 3-pin). Wouldn't give much more than 0.5 amps before the voltage began to fall significantly. There was also a youtube video where someone demonstrated the same failing and also opened it up and found several safety concerns.

Edit. found the video. https://www.youtube.com/watch?v=T88ej64aXUM

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clicky
Posts: 383
Joined: Thu Oct 25, 2012 7:34 am

Re: Max USB Drives

Wed Aug 28, 2019 4:13 pm

ryan810cows wrote:
Wed Aug 28, 2019 3:38 pm
Understood.
But i have FREE 500 gb HDD's from work b/c we change them out so often as a preventive measure and most of the time they are happy and healthy still.

That would be me at 5 tb of storage in total if i just use them as individual HDD's and not do any RAID.
Just imagine you do have some fancy self healing/triple redundant/hot pluggable raid... :D
With all the free HDs...

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