Automatically turn on after power supply gets off

[micutu82]

Hello,

I have read that a raspberry pi doesn't have a BIOS like a normal computer (Desktop or laptop).

The question is:

If the power supply gets off and it's come back after , let's say...5-10 minutes, raspberry is starting automatically, without any problem?

At the newer computers in BIOS we have an option to do that, to start again by itself when the power supply is come back

Thank you and sorry for my English

[trejan]

If the power supply gets off and it's come back after , let's say...5-10 minutes, raspberry is starting automatically, without any problem?

Yes. The Pi will always try to start after power has been restored.

[micutu82]

Thank you for your fast reply.

But the OS could have problems? if then it's running a process, or maybe SD card may have problems
Can i run the OS from a hdd on USB? (of course with its own power supply)


LE

From this documentation i understood that i can't boot on raspberry pi 4 from a hdd on USB

https://www.raspberrypi.org/documentati ... teeprom.md

[W. H. Heydt]

Thank you for your fast reply.

But the OS could have problems? if then it's running a process, or maybe SD card may have problems
Can i run the OS from a hdd on USB? (of course with its own power supply)

Yes, you can put anything from the root file system to the whole boot process (depending on model) on an HDD. While that will *reduce* the chances of file system corruption from losing power, it won't solve the problem. The problem is that, if file system activity is taking place when the power fails, there may be file system corruption. The corruption may or may not be recoverable.

There are several pretty good solutions to your problem. Things like "read only" file systems, for instance. But if you want a normally running system, then your first step should be to use a UPS to reduce the chance of an uncontrolled power outage. The reason I say "reduce" rather than "eliminate" is because a UPS can fail on its own, though it's not particularly likely and routine maintanence can make the chances quite low.

[emma1997]

The problem is shutting down w/o permission because of SD corruption, not the powerup part. Modern HD are more resistant to damage in that case and flash drive or SSD even more so.

[micutu82]

Thank you for your fast reply.

But the OS could have problems? if then it's running a process, or maybe SD card may have problems
Can i run the OS from a hdd on USB? (of course with its own power supply)

Yes, you can put anything from the root file system to the whole boot process (depending on model) on an HDD. While that will *reduce* the chances of file system corruption from losing power, it won't solve the problem. The problem is that, if file system activity is taking place when the power fails, there may be file system corruption. The corruption may or may not be recoverable.

There are several pretty good solutions to your problem. Things like "read only" file systems, for instance. But if you want a normally running system, then your first step should be to use a UPS to reduce the chance of an uncontrolled power outage. The reason I say "reduce" rather than "eliminate" is because a UPS can fail on its own, though it's not particularly likely and routine maintanence can make the chances quite low.

Yes, thank you very much for your fast answer. I want to make my own router It's only a hobby . I don't think i will buy an UPS, probably i will use an ssd on usb. Do i need a different power supply for ssd? I forgot to say that i want to buy a raspberry pi 4

[micutu82]

The problem is shutting down w/o permission because of SD corruption, not the powerup part. Modern HD are more resistant to damage in that case and flash drive or SSD even more so.

Then, first i will try with an HD card or a flash drive. Anyway, for the first time when i boot up, i have to use a sd card, right? for raspberry pi 4
Thank you

[W. H. Heydt]

Thank you for your fast reply.

But the OS could have problems? if then it's running a process, or maybe SD card may have problems
Can i run the OS from a hdd on USB? (of course with its own power supply)

Yes, you can put anything from the root file system to the whole boot process (depending on model) on an HDD. While that will *reduce* the chances of file system corruption from losing power, it won't solve the problem. The problem is that, if file system activity is taking place when the power fails, there may be file system corruption. The corruption may or may not be recoverable.

There are several pretty good solutions to your problem. Things like "read only" file systems, for instance. But if you want a normally running system, then your first step should be to use a UPS to reduce the chance of an uncontrolled power outage. The reason I say "reduce" rather than "eliminate" is because a UPS can fail on its own, though it's not particularly likely and routine maintanence can make the chances quite low.

Yes, thank you very much for your fast answer. I want to make my own router It's only a hobby . I don't think i will buy an UPS, probably i will use an ssd on usb. Do i need a different power supply for ssd? I forgot to say that i want to buy a raspberry pi 4

At present, I have 3 Pi4B4 each with an attached HP 120GB SSD. The SSDs run from their respective Pis. I also have a Pi3B+ powering and booting from a WD 314GB PiDrive. All of those Pis are behind a UPS. You can get a small (about 350VA) for less than $40, at least the last time I bought one.

Just be sure to check the specs on your chosen SSD/HDD to be sure that it will run from a 5v supply (typical of 2.5" form factor drives) and whose maximum draw is less than the 1.2A a Pi can supply to the USB ports. The SSDs I'm using are all rated at less than 1.5W (300mA) max for writing. The PiDrive was specially designed to powered from a Pi, including reduced starting in-rush current, which is what will rule out many HDDs.

I should point out that all of my network equipment--modem, routers, and switches--are behind UPSes, so just because your Pi project is to make a router is a not reason to omit proper power protection.

[micutu82]

Yes, you can put anything from the root file system to the whole boot process (depending on model) on an HDD. While that will *reduce* the chances of file system corruption from losing power, it won't solve the problem. The problem is that, if file system activity is taking place when the power fails, there may be file system corruption. The corruption may or may not be recoverable.

There are several pretty good solutions to your problem. Things like "read only" file systems, for instance. But if you want a normally running system, then your first step should be to use a UPS to reduce the chance of an uncontrolled power outage. The reason I say "reduce" rather than "eliminate" is because a UPS can fail on its own, though it's not particularly likely and routine maintanence can make the chances quite low.

Yes, thank you very much for your fast answer. I want to make my own router It's only a hobby . I don't think i will buy an UPS, probably i will use an ssd on usb. Do i need a different power supply for ssd? I forgot to say that i want to buy a raspberry pi 4

At present, I have 3 Pi4B4 each with an attached HP 120GB SSD. The SSDs run from their respective Pis. I also have a Pi3B+ powering and booting from a WD 314GB PiDrive. All of those Pis are behind a UPS. You can get a small (about 350VA) for less than $40, at least the last time I bought one.

Just be sure to check the specs on your chosen SSD/HDD to be sure that it will run from a 5v supply (typical of 2.5" form factor drives) and whose maximum draw is less than the 1.2A a Pi can supply to the USB ports. The SSDs I'm using are all rated at less than 1.5W (300mA) max for writing. The PiDrive was specially designed to powered from a Pi, including reduced starting in-rush current, which is what will rule out many HDDs.

I should point out that all of my network equipment--modem, routers, and switches--are behind UPSes, so just because your Pi project is to make a router is a not reason to omit proper power protection.

Very good information. I didn't know that exist special hdd drive for raspberry pi. After i will buy a pi i will bother you, if you don't mind, with questions about hdd

If it will be an uncontrolled power outage and even if i would have an UPS, i still won't be online. My ISP doesn't have UPS for his DSLAM

[W. H. Heydt]

Very good information. I didn't know that exist special hdd drive for raspberry pi. After i will buy a pi i will bother you, if you don't mind, with questions about hdd

For whatever reasons--probably didn't sell enough--WD discontinued the PiDrives.

If it will be an uncontrolled power outage and even if i would have an UPS, i still won't be online. My ISP doesn't have UPS for his DSLAM

That seems....unlikely. Or...short sighted. Or...just plain incompetent. If your ISP isn't able or willing to provide emergency backup power for their own equipment, I'd be looking for another ISP...fast.

[HawaiianPi]

Hello,

I have read that a raspberry pi doesn't have a BIOS like a normal computer (Desktop or laptop).

It doesn't have an on-board BIOS. Many of the BIOS functions found on Windows computers are handled in the "boot" partition of a Raspbian SD card. It's a different system, but it's still quite capable and versatile.

If the power supply gets off and it's come back after , let's say...5-10 minutes, raspberry is starting automatically, without any problem?

At the newer computers in BIOS we have an option to do that, to start again by itself when the power supply is come back

Thank you and sorry for my English

Whenever powered on, a Raspberry Pi computer will always try to boot the system. What it can't do (as far as I know) is not boot after a power interruption (like you can configure in some other BIOS systems).

But the OS could have problems? if then it's running a process, or maybe SD card may have problems
Can i run the OS from a hdd on USB? (of course with its own power supply)

Whenever the system is powered off without a proper software shutdown you may have problems. This is true even with SSD or HDD. To protect against that you can use an uninterruptible power supply (UPS) or read-only file system. Another option is to net-boot (boot the system from a network resource), which the Pi3 and Pi4 can do.

From this documentation i understood that i can't boot on raspberry pi 4 from a hdd on USB

Not yet. Netbooting was added first, and they are working on adding USB boot now. In the meantime you can have /boot on an SD card and run the main OS file system from a USB drive (that's what I do with my Pi 4B2).

Network booting will allow you to boot with no SD card, but it will be slower than SD or SD+USB booting. You could combine both by starting a cardless boot from the network, then running the OS from an SSD (haven't tried that yet, but it should be possible).

If it will be an uncontrolled power outage and even if i would have an UPS, i still won't be online. My ISP doesn't have UPS for his DSLAM

If your ISP supplied modem+router was connected to a UPS along with your computer, I bet it would work. In my experience both the Internet and phones continue to work (at least for awhile).


Raspberry Pi 3B, 3B+ and 4B models can usually run a single 2.5 inch HDD or dual SSD from their USB ports using only the official power supply. Of course that depends on the drives (some are more power hungry than others), but I have a few 3B/3B+ models running off of SSD, and I have tested the Pi 4B with dual SSD (/boot on SD card with main OS on top SSD and /home on bottom SSD). It worked fine, not only with the official 3A power supply, but even with the older 2.5A micro-USB PSU with a USB-C adapter.

[micutu82]

Whenever powered on, a Raspberry Pi computer will always try to boot the system. What it can't do (as far as I know) is not boot after a power interruption (like you can configure in some other BIOS system

So, if i understood ok, i can't use it as a router without an UPS. After a power outage, it will not boot, it will not start by itself

[wildfire]

Whenever powered on, a Raspberry Pi computer will always try to boot the system. What it can't do (as far as I know) is not boot after a power interruption (like you can configure in some other BIOS system

So, if i understood ok, i can't use it as a router without an UPS. After a power outage, it will not boot, it will not start by itself

The opposite, you can't set the Pi to NOT boot when power is restored after a power failure*, whether the attempt to boot is successful or not depends on the state of boot media and/or file system.

*It's likely this is possible but would require additional hardware.

[HawaiianPi]

So, if i understood ok, i can't use it as a router without an UPS. After a power outage, it will not boot, it will not start by itself

It will always try to boot, and more often than not it will succeed. If your power doesn't go out often, you might be okay.

However, corrupting the file system is always a possibility when power is interrupted without a proper shutdown. To avoid that you either need a more robust file system (read-only or RAM based), or you need to prevent unscheduled power interruptions (UPS).

A read-only file system is never written to in normal operation, so it won't get corrupted, but as you might have guessed by now, if you want to save data or update the OS it complicates things (it can be done, just not as easily as with a read-write OS). On Pi computers configuring just the boot partition for read-only helps protect the system, while still allowing some data manipulation.

RAM based OS is a similar concept, except in this case the entire OS loads into and runs from RAM, so every reboot is a fresh start. Tiny Core Linux is such an OS, and they have a version for the Pi (although I'm not sure if they have Pi4 support yet).

[micutu82]

So, if i understood ok, i can't use it as a router without an UPS. After a power outage, it will not boot, it will not start by itself

It will always try to boot, and more often than not it will succeed. If your power doesn't go out often, you might be okay.

However, corrupting the file system is always a possibility when power is interrupted without a proper shutdown. To avoid that you either need a more robust file system (read-only or RAM based), or you need to prevent unscheduled power interruptions (UPS).

A read-only file system is never written to in normal operation, so it won't get corrupted, but as you might have guessed by now, if you want to save data or update the OS it complicates things (it can be done, just not as easily as with a read-write OS). On Pi computers configuring just the boot partition for read-only helps protect the system, while still allowing some data manipulation.

RAM based OS is a similar concept, except in this case the entire OS loads into and runs from RAM, so every reboot is a fresh start. Tiny Core Linux is such an OS, and they have a version for the Pi (although I'm not sure if they have Pi4 support yet).

Thank you very much for your fast answer and for clarification. I don't know linux so well, so the easiest way is to buy an UPS . Expensive hobby

[fruitoftheloom]

So, if i understood ok, i can't use it as a router without an UPS. After a power outage, it will not boot, it will not start by itself

It will always try to boot, and more often than not it will succeed. If your power doesn't go out often, you might be okay.

However, corrupting the file system is always a possibility when power is interrupted without a proper shutdown. To avoid that you either need a more robust file system (read-only or RAM based), or you need to prevent unscheduled power interruptions (UPS).

A read-only file system is never written to in normal operation, so it won't get corrupted, but as you might have guessed by now, if you want to save data or update the OS it complicates things (it can be done, just not as easily as with a read-write OS). On Pi computers configuring just the boot partition for read-only helps protect the system, while still allowing some data manipulation.

RAM based OS is a similar concept, except in this case the entire OS loads into and runs from RAM, so every reboot is a fresh start. Tiny Core Linux is such an OS, and they have a version for the Pi (although I'm not sure if they have Pi4 support yet).

Thank you very much for your fast answer and for clarification. I don't know linux so well, so the easiest way is to buy an UPS . Expensive hobby

How can you infer that the Raspberry Pi is costing money, when your issue is with your Electricity Provider


https://uk.pi-supply.com/products/pi-up ... spberry-pi

[micutu82]

It was a joke i forgot to put the quotes

[Abnormalized]

If the power supply gets off and it's come back after , let's say...5-10 minutes.

I wonder what the power supply's mother thinks ( ͡• ͜ʖ ͡• )



But yes, the Pi turns on when it receives power. You can buy little switches on the usb-c cable that allow you to leave the cord plugged in without the Pi receiving power. Though I would still unplug it if you are gonna access the GPIO pins.