From: tnp@invalid.invalid   
      
   On 11/05/2024 17:22, Pancho wrote:   
   > On 11/05/2024 09:53, The Natural Philosopher wrote:   
   >> Well it was always going to be a shot in the dark...:-)   
   >>   
   >> And I think I can confirm that a Pi4 cannot drive three SSDs over USB   
   >> unaided.   
   >> As soon as I tried to rsync a new drive as a backup, via NFS, I   
   >> started to get disk errors. On unrelated disks...not involved in the   
   >> transfer.   
   >>   
   >> The PI4 had a TV card on it that gets pretty hot so I removed that to   
   >> reduce load on the power supply, but significantly it made *no   
   >> difference at all*.   
   >>   
   >> I hooked up a n HDMI screen to monitor the console messages and it was   
   >> full of disk errors of one sort or another.   
   >>   
   >> Not necessarily related to the drive in use.   
   >>   
   >> My tentative conclusion, which I would like some opinion on, is that   
   >> it is the USB power limit that is causing the problems, not the   
   >> overall power draw. As that would have bee relieved by removing the TV   
   >> hat.   
   >>   
   >> Now as far as I can tell the total USB power available on the PI4   
   >> equates to 1200mA.   
   >>   
   >> But on the Pi 5 that increase to 1600mA, provided you tell the board   
   >> it has a 'high power supply'.   
   >>   
   >   
   > 1600mA isn't that much more than 1200mA. There is quite a difference in   
   > the power requirements of different SSDs. Kingston A400 drives have a   
   > max wattage of about 1.5 watts. Some other SSD drives quote up to 5   
   > watts. NVME drives even more.   
   >   
   > So If I were you, I would want to understand the drives you have, know   
   > their power consumption, before making a decision.   
   >   
   I did quite a lot of research before picking the drives that I did   
      
   > FWIW, I only have one USB SSD running off an unpowered cable. The   
   > additional drives use a secondary power supply, but I use spinning HDDs   
   > as well as SSDs, so I needed to.   
   >   
   > Also, the Pi 5 is a great computer, so worth buying just for fun. You'll   
   > find something to use it for.   
   >   
   Indeed. That was my thought. I could use it as another media driver for   
   the now redundant TVs (redundant because I have watched and/or recorded   
   all the repeats of all the shows I missed when working for a living, and   
   wall to wall propaganda and adverts is all that is left ...) and stick   
   high definition audio on it to play my music   
      
   >   
      
   --   
   "It is an established fact to 97% confidence limits that left wing   
   conspirators see right wing conspiracies everywhere"   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)