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Multiple hard drives keep disconnecting [solved]

Posted: Mon Oct 28, 2019 12:25 am
by solidsnake
Hi,

I have connected 3 hard drives (not externally powered) to the pi. But they periodically disconnect without any error. It's usually works fine when I restart the pi but only for 5 mins. Is this a power output problem? How can I supply more power to the pi? Or can I supply more power to the hard drives if they are not externally powered?

Thanks

Re: Multiple hard drives keep disconnecting

Posted: Mon Oct 28, 2019 12:27 am
by default_user8
Are you using a usb hub?

Re: Multiple hard drives keep disconnecting

Posted: Mon Oct 28, 2019 1:06 am
by solidsnake
No, I'm not. All hard disks are plugged into the pi directly

Re: Multiple hard drives keep disconnecting

Posted: Mon Oct 28, 2019 1:24 am
by default_user8
I'm surprised your pi is booting with all those drives plugged in directly. Try using a usb hub and see if your problem persist.

P.S. I see you asked this same question on your other thread about your plex server, you should refrain from redirecting threads to help get your questions answered in a timely fashion and to help others when they search for answers to similar questions they may have.

Re: Multiple hard drives keep disconnecting

Posted: Mon Oct 28, 2019 4:57 am
by RossDv8
I got around a similar problem by using splitter cables, which have 2 x male and 1 x female USB ends. One male has a red band (power), and is plugged into something with USB power, like a 2A phone charger. The other male end (data) is plugged into either a non-powered USB hub, or a Pi USB socket. Then the external drive is plugged into the female socket.

That should relieve some of the power drain on the Pi, although my cable sometimes seem to leak a little power back into the Pi USB socket..
Anyway, I use that to spin up a 3TB drive that otherwise just sits and clicks when plugged directly into the Pi USB3 socket. The splitter cables are only a few dollars each on ebay or Amazon (might be why mine feeds some power back...) But I've been doing it on the Pi 3, 3B+ and 4, with nothing blowing up yet..

It might be a GOOD IDEA to 'Eject' any external drives before you shutdown or reboot - probably doesn't matter about shutdown, but especially before you reboot.
I found that leaving an external drive mounted on reboot sometimes stops reboot from happening,

Re: Multiple hard drives keep disconnecting

Posted: Mon Oct 28, 2019 12:16 pm
by thagrol
solidsnake wrote:
Mon Oct 28, 2019 12:25 am
Hi,

I have connected 3 hard drives (not externally powered) to the pi. But they periodically disconnect without any error. It's usually works fine when I restart the pi but only for 5 mins. Is this a power output problem? How can I supply more power to the pi? Or can I supply more power to the hard drives if they are not externally powered?

Thanks
Certainly sounds like a power problem. Which model Pi and what are you uing for a PSU?

Try using a self powered UBS hub and including "nofail" in your mount options. "nofail" means your system will continue to boot even if the mount fails.

A USB hub without its own power supply won't help and may make things worse due the, admittedly small, additional power drain.

Re: Multiple hard drives keep disconnecting

Posted: Mon Oct 28, 2019 1:22 pm
by solidsnake
Thanks everyone. I've ordered a powered USB hub which I'll try tomorrow and let you know if the problem still persists.

@thagrol - I have pi 4 and use a 5A power supply

Re: Multiple hard drives keep disconnecting

Posted: Mon Oct 28, 2019 1:51 pm
by thagrol
solidsnake wrote:
Mon Oct 28, 2019 1:22 pm
Thanks everyone. I've ordered a powered USB hub which I'll try tomorrow and let you know if the problem still persists.

@thagrol - I have pi 4 and use a 5A power supply
5 amp is way over the recommended amount :) but...

Even if the PSU is capable of providing 5 amps, the 4B can only provide 1.2 amps across all connected USB devices. Anything the PSU can provide above 1.2A + what the 4B needs won't be drawn.

Current required to initially spin up multiple HDD can easily exceed the 1.2A limit.

Re: Multiple hard drives keep disconnecting

Posted: Sun Nov 03, 2019 1:36 am
by solidsnake
Update - the problem was resolved after I used a powered USB hub and changed the cables. Don't know whether it was the cables of the power but I'm not too bothered as it's working perfectly now