Andyroo

Re: Is there a cheap and reliable UPS for raspberry pi 3b+?

Fri Mar 08, 2019 3:46 pm

Man, it must be tough to live in a world where you got to censor ....
Please remember children come on the forum and, unlike most of the net, it aims to be family friendly :)

W. H. Heydt
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Re: Is there a cheap and reliable UPS for raspberry pi 3b+?

Fri Mar 08, 2019 4:24 pm

crocket wrote:
Fri Mar 08, 2019 2:49 pm
W. H. Heydt wrote:
Fri Mar 08, 2019 2:42 pm
There are some parameters that aren't spelled out. Such as, how long a power outage do you expect to ride out? What do you consider to be "cheap"?

For protecting a transportable system (that is, one that I can pack up, take with me, and set up when I arrive at my destination) I use: https://www.frys.com/product/8039934?si ... IN_RSLT_PG The cost is a bit more than a Pi, itself, it's not particularly heavy, and it will ride out *most* power outages. Plus--like any UPS--it includes line conditioning and surge protection. At 3.5 lbs., it is reasonably portable.
Cheap means it's not more expensive than Pi itself. I wanted up to 10 minutes of operation after power loss so that I could shut it down properly.
It's hard to find commercial products that can do real work and still cost less than a Pi. Good keyboards, monitors, even some mice cost more than a Pi. The UPS I linked to says that it will run for 8 minutes at half load. Half load is a bit over 125W. A Pi requires--at most--about 13W. If you add in losses in the PSU, you'll still well under 20W. Therefore,one might expect it to run a Pi for an hour or more. Plus, you're not going to get a battery solution that is much cheaper than Lead Acid, though you pay for the low cost with a low watt/pound value.

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Re: Is there a cheap and reliable UPS for raspberry pi 3b+?

Fri Mar 08, 2019 6:35 pm

crocket wrote:
Fri Mar 08, 2019 1:49 pm
mahjongg wrote:
Fri Mar 08, 2019 1:33 pm
Also, please don't swear, I get complaints I have to handle by applying censorship, which I hate to do....
Man, it must be tough to live in a world where you got to censor chips.
Even worse, I have to perma-ban people who don't realize this is a family friendly forum..... :twisted: :roll:

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Re: Is there a cheap and reliable UPS for raspberry pi 3b+?

Fri Mar 08, 2019 11:55 pm

W. H. Heydt wrote:
Fri Mar 08, 2019 4:24 pm
Plus, you're not going to get a battery solution that is much cheaper than Lead Acid, though you pay for the low cost with a low watt/pound value.
I guess I will buy something like https://www.frys.com/product/8039934 with a battery if I want a UPS.

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Imperf3kt
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Re: Is there a cheap and reliable UPS for raspberry pi 3b+?

Sat Mar 09, 2019 12:10 am

mahjongg wrote:
Fri Mar 08, 2019 6:35 pm
Even worse, I have to perma-ban people who don't realize this is a family friendly forum..... :twisted: :roll:
I believe this is permaban repeat offenders, is it not. Surely first time offense gets a written warning, second offense gets a potential temp ban, Third or more offences summon the permaban hammer.
________________________________

If you had a soldering iron, I would have suggested something like the MP2636 plus a Lithium ion or lithium polymer battery. The module doesn't actually require soldering, but in order to avoid the low voltage warning, I found the USB connectors were causing too much resistance, so soldering your own wiring is required.

The MP2636 is about $8USD, a battery depends on what you get but a 5Ah tablet battery will only set you back about $15 - $20 USD
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crocket
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Re: Is there a cheap and reliable UPS for raspberry pi 3b+?

Sat Mar 09, 2019 1:37 am

Imperf3kt wrote:
Sat Mar 09, 2019 12:10 am
I believe this is permaban repeat offenders, is it not. Surely first time offense gets a written warning, second offense gets a potential temp ban, Third or more offences summon the permaban hammer.
________________________________

If you had a soldering iron, I would have suggested something like the MP2636 plus a Lithium ion or lithium polymer battery. The module doesn't actually require soldering, but in order to avoid the low voltage warning, I found the USB connectors were causing too much resistance, so soldering your own wiring is required.

The MP2636 is about $8USD, a battery depends on what you get but a 5Ah tablet battery will only set you back about $15 - $20 USD
Demonizing swearing by a threat of permaban seems scarier to children than swearing itself. Empathy and tolerance create a better atmosphere for a family-friendly forum than demonization. It might sound counter-intuitive.

Anyway, I decided to buy a proper APC UPS to protect my entire electronic setup. I decided to not be poor. Buying a cheaper flimsy UPS for only Raspberry Pi or not having a proper UPS for my precious data may prove to be false frugality in the long run. A proper UPS is the cheapest insurance policy. Another counter-intuitive insight.

bholland84
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Re: Is there a cheap and reliable UPS for raspberry pi 3b+?

Sat Mar 09, 2019 3:50 am

Lets get real here for a second. The Rpi3b+ is a whole 35$. An 8gb SD card, more than enough for Raspbian desktop installs is 10$ while a 16GB SD card is 20$.

If you manage to destroy your rpi3, you are out 35$. If you manage to destroy your SD card, you are out about 10$.

If you absolutely NEED 24/7/365 uninterrupted power to run a pi, 80$ is nothing. Actually, I would assume that the few hundred dollars for a massive UPS is nothing, given your needs. The requirement for a five 9's uptime is so rare that you probably need to be making money from whatever it is you are doing and if you are making money from it, that many hundreds of dollars UPS now is just the cost of doing business.

So really, you need to ask yourself a few questions. Do you absolutely need 99.999% uptime (less than an hour of downtime every year) or is that a nice to have? File systems, particularly journaled systems, are designed around power loss. Hardware is designed for power loss. The huge issue actually is power spikes, not a loss. True power spikes are very rare and require something huge for your house, apartment, or condo on the order of about a million jouls. That 13,000 jouls outlet bar is not going to do anything with a real power surge and at that point, your pi is probably the least of your concerns.

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Re: Is there a cheap and reliable UPS for raspberry pi 3b+?

Sat Mar 09, 2019 4:25 am

bholland84 wrote:
Sat Mar 09, 2019 3:50 am
So really, you need to ask yourself a few questions. Do you absolutely need 99.999% uptime (less than an hour of downtime every year) or is that a nice to have? File systems, particularly journaled systems, are designed around power loss. Hardware is designed for power loss. The huge issue actually is power spikes, not a loss. True power spikes are very rare and require something huge for your house, apartment, or condo on the order of about a million jouls. That 13,000 jouls outlet bar is not going to do anything with a real power surge and at that point, your pi is probably the least of your concerns.
In a few years, I will do critical business work on my computer. Then, a UPS can be useful for protection of unsaved data from blackouts.

Can a power outage cause "painful" file corruptions that will cause harm to important data beyond repair? Will my hourly ZFS snapshots survive power outages?

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Re: Is there a cheap and reliable UPS for raspberry pi 3b+?

Sat Mar 09, 2019 10:17 am

crocket wrote:
Sat Mar 09, 2019 4:25 am
In a few years, I will do critical business work on my computer. Then, a UPS can be useful for protection of unsaved data from blackouts.
How often do you experience blackouts ? Yearly ? Monthly ? Weekly ? Daily ? Hourly ?
crocket wrote:
Sat Mar 09, 2019 4:25 am
Can a power outage cause "painful" file corruptions that will cause harm to important data beyond repair?
Yes
crocket wrote:
Sat Mar 09, 2019 4:25 am
Will my hourly ZFS snapshots survive power outages?
A definitive maybe. It depends on a lot more than just being a ZFS snapshot, it depends on the implementation, the procedures and the environment.

IMHO you are worrying too much about reliability (at this moment in time). Your first priority should be to implement a backup concept that allows you to recover from data loss within a reasonable period of time with the minimum loss of data and minimum loss of income. ZFS snapshots are not backup when it comes to disaster recovery, it only helps with accidental loss of data if the snapshot stays on the primary storage medium.
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Re: Is there a cheap and reliable UPS for raspberry pi 3b+?

Sat Mar 09, 2019 11:32 am

Ernst wrote:
Sat Mar 09, 2019 10:17 am
How often do you experience blackouts ? Yearly ? Monthly ? Weekly ? Daily ? Hourly ?

IMHO you are worrying too much about reliability (at this moment in time). Your first priority should be to implement a backup concept that allows you to recover from data loss within a reasonable period of time with the minimum loss of data and minimum loss of income. ZFS snapshots are not backup when it comes to disaster recovery, it only helps with accidental loss of data if the snapshot stays on the primary storage medium.
I experience one blackout per several years. They are usually planned maintenance blackouts that I was notified of in advance. Only one was unexpected national blackout which happened about 8 years ago. I think I experienced 3~4 blackouts in 20 years. The longest blackout which was the unexpected national blackout was several hours. People say it was caused by inefficiency, corruption, and embezzlement. Maintenance blackouts for my apartment building usually last 1~2 hours.

I think I experienced a momentary brownout once in my lifetime, but I could have experienced it more than once without knowing.

Also, you can send ZFS snapshots to another computer, so a ZFS snapshot can be turned into a backup. I'm probably going to send ZFS snapshots of my SD card from RPi to my desktop on an automated schedule.
Ernst wrote:
Sat Mar 09, 2019 10:17 am
A definitive maybe. It depends on a lot more than just being a ZFS snapshot, it depends on the implementation, the procedures and the environment.
I run zfsonlinux on my gentoo linux desktop. The system is updated bi-weekly. The root ZFS pool is in ZFS raid 1. The data ZFS pool is also in ZFS raid 1. Every ZFS pool maintains latest hourly and daily snapshots.
Last edited by crocket on Sat Mar 09, 2019 11:53 am, edited 2 times in total.

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Re: Is there a cheap and reliable UPS for raspberry pi 3b+?

Sat Mar 09, 2019 11:45 am

bholland84 wrote:
Sat Mar 09, 2019 3:50 am
The huge issue actually is power spikes, not a loss. True power spikes are very rare and require something huge for your house, apartment, or condo on the order of about a million jouls. That 13,000 jouls outlet bar is not going to do anything with a real power surge and at that point, your pi is probably the least of your concerns.
I once had a lightning strike destroy the transformer out the front of the house I was living in. At the time I had literally just purchased a surge protector powerboard and installed it a few hours before the storm.

When the lightning hit, the surge protector jumped into the air, as far as the cable allowed, a huge blue spark scorched the carpet and the surge protector shattered, blasting all my connected equipment plugs out in random directions.

The next day, when the storm had passed, I checked my devices and nothing was damaged, so I'd say to some extent, yes, they do help. Though they didn't do much for the carpet lol.
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Re: Is there a cheap and reliable UPS for raspberry pi 3b+?

Sat Mar 09, 2019 11:51 am

crocket wrote:
Sat Mar 09, 2019 11:32 am
I experience one blackout per several years. They are usually planned maintenance blackouts that I was notified of in advance. Only one was unexpected national blackout. I think I experienced 3~4 blackouts in 20 years. The longest blackout which was the unexpected national blackout was several hours. Some people said our enemies caused national blackout as a form of cyber attack. Maintenance blackouts for my apartment building usually last 1~2 hours.

I think I experienced a momentary brownout once in my lifetime, but I could have experienced it more than once without knowing.
With the exceptionally low number of blackouts you must assume that the UPS will fail when you think you need it most.
crocket wrote:
Sat Mar 09, 2019 11:32 am
Also, you can send ZFS snapshots to another computer, so a ZFS snapshot can be turned into a backup.
Why do you use the word "can" ? Have you verified that a) you are able to send ZFS snapshots to another computer ? b) use a ZFS snapshot as a backup and source for a disaster recovery ? Have you verified that this can be done on an automated schedule within the time available ? Have you verified that you are able to store backup data at an offsite location that can be used on different hardware if needed ? Are you sure that ZFS snapshots will be sufficient to protect your valuable data ?
crocket wrote:
Sat Mar 09, 2019 11:32 am
I'm probably going to send ZFS snapshots of my SD card from RPi to my desktop on an automated schedule.
Please explain how you have implemented ZFS on the SD card on the RPi.
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Re: Is there a cheap and reliable UPS for raspberry pi 3b+?

Sat Mar 09, 2019 12:00 pm

Ernst wrote:
Sat Mar 09, 2019 11:51 am
With the exceptionally low number of blackouts you must assume that the UPS will fail when you think you need it most.
Do you suggest that UPS is not going to help much in my situation?
Ernst wrote:
Sat Mar 09, 2019 11:51 am
Why do you use the word "can" ? Have you verified that a) you are able to send ZFS snapshots to another computer ? b) use a ZFS snapshot as a backup and source for a disaster recovery ? Have you verified that this can be done on an automated schedule within the time available ? Have you verified that you are able to store backup data at an offsite location that can be used on different hardware if needed ? Are you sure that ZFS snapshots will be sufficient to protect your valuable data ?
According to https://github.com/jimsalterjrs/sanoid/#syncoid, "syncoid -r root@remotehost:data/images/vm backup/images/vm" would pull a ZFS dataset and all its associated snapshots from a remote machine. I think I can write a cron job to make my desktop pull the ZFS dataset and its children snapshots from my SD card. Syncoid is an incremental backup solution. Sanoid would make hourly and daily snapshots automatically on RPi. Syncoid would pull the ZFS dataset and its associated snapshots from the SD card remotely. Only the first syncoid invocation would require scraping gigabytes. The subsequent invocations would just pull differences.
Ernst wrote:
Sat Mar 09, 2019 11:51 am
Please explain how you have implemented ZFS on the SD card on the RPi.
I have 32GB SD card, but RPi 3 is in transit from china. I will basically make a ZFS pool and install gentoo on it. It's not very different from doing it for my desktop computer. After all, RPi 3 is just a computer like any other.
Last edited by crocket on Sat Mar 09, 2019 12:27 pm, edited 1 time in total.

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Re: Is there a cheap and reliable UPS for raspberry pi 3b+?

Sat Mar 09, 2019 12:22 pm

crocket wrote:
Sat Mar 09, 2019 12:00 pm
Ernst wrote:
Sat Mar 09, 2019 11:51 am
With the exceptionally low number of blackouts you must assume that the UPS will fail when you think you need it most.
Do you suggest that UPS is not going to help much in my situation?
It may, or it may not, it depends on the maintenance and testing procedures.
With a proper UPS there will be management software to monitor the operations and the state of the batteries.
And the UPS communicates with the host and/or management software to provide information on the mains input enabling the host(s) to do a controlled shutdown if the power outage is not resolved within the maximum runtime of the UPS. A low cost UPS will unlikely provide these features and the chance exists that the battery fails when needed most.
crocket wrote:
Sat Mar 09, 2019 12:00 pm
Ernst wrote:
Sat Mar 09, 2019 11:51 am
Why do you use the word "can" ? Have you verified that a) you are able to send ZFS snapshots to another computer ? b) use a ZFS snapshot as a backup and source for a disaster recovery ? Have you verified that this can be done on an automated schedule within the time available ? Have you verified that you are able to store backup data at an offsite location that can be used on different hardware if needed ? Are you sure that ZFS snapshots will be sufficient to protect your valuable data ?
According to https://github.com/jimsalterjrs/sanoid/#syncoid, "syncoid data/images/vm root@remotehost:backup/images/vm" would send a ZFS snapshot to a remote machine. It can be done automatically on a schedule.
In other words: you know that it can be done but you have not done extensive testing and evaluation.
Also you have limited knowledge of the purpose of snapshots, this might be worthwhile to study.
crocket wrote:
Sat Mar 09, 2019 12:00 pm
Ernst wrote:
Sat Mar 09, 2019 11:51 am
Please explain how you have implemented ZFS on the SD card on the RPi.
I have 32GB SD card, but RPi 3 is in transit from china. I will basically make a ZFS pool and install gentoo on it. It's not very different from doing it for my desktop computer.
In other words you have not implemented anything on the RPi 3 yet.
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Re: Is there a cheap and reliable UPS for raspberry pi 3b+?

Sat Mar 09, 2019 12:33 pm

Ernst wrote:
Sat Mar 09, 2019 12:22 pm
With a proper UPS there will be management software to monitor the operations and the state of the batteries.
And the UPS communicates with the host and/or management software to provide information on the mains input enabling the host(s) to do a controlled shutdown if the power outage is not resolved within the maximum runtime of the UPS. A low cost UPS will unlikely provide these features and the chance exists that the battery fails when needed most.
APC BE-550 supports reporting of its status and whether it's connected to mains power through a data port.
You can install "apc"upsd from a gentoo repository to enable RPi to interact with BE-550. BE-550 costs ~93 USD in my region.

I believe I can configure apcupsd to trigger shutdown for RPi and my desktop minutes after a power loss.
Last edited by crocket on Sat Mar 09, 2019 12:36 pm, edited 1 time in total.

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Re: Is there a cheap and reliable UPS for raspberry pi 3b+?

Sat Mar 09, 2019 12:35 pm

crocket wrote:
Sat Mar 09, 2019 12:00 pm
I have 32GB SD card, but RPi 3 is in transit from china. I will basically make a ZFS pool and install gentoo on it. It's not very different from doing it for my desktop computer. After all, RPi 3 is just a computer like any other.
It is very annoying when you edit your posts AFTER a reply has been posted.
Last edited by Ernst on Sat Mar 09, 2019 12:37 pm, edited 1 time in total.
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Re: Is there a cheap and reliable UPS for raspberry pi 3b+?

Sat Mar 09, 2019 12:37 pm

crocket wrote:
Sat Mar 09, 2019 12:33 pm
Ernst wrote:
Sat Mar 09, 2019 12:22 pm
With a proper UPS there will be management software to monitor the operations and the state of the batteries.
And the UPS communicates with the host and/or management software to provide information on the mains input enabling the host(s) to do a controlled shutdown if the power outage is not resolved within the maximum runtime of the UPS. A low cost UPS will unlikely provide these features and the chance exists that the battery fails when needed most.
APC BE-550 supports reporting of its status and whether it's connected to mains power through a data port.
You can install "apc"upsd from a gentoo repository to enable RPi to interact with BE-550. BE-550 costs ~93 USD in my region.

I believe I can configure apcupsd to trigger shutdown for RPi and my desktop minutes after a power loss.
Please come back when you have done a POC.
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Re: Is there a cheap and reliable UPS for raspberry pi 3b+?

Sat Mar 09, 2019 12:40 pm

[Anecdote]
We had a mission critical database server, protected by a UPS. Our IT support company paid a visit.
Tech: I'll just test the UPS.
Manager: Let me shut down the database server first.
Tech: Oh, it will be alright.
Tech pulls power. It wasn't alright. Fortunately the system could be repaired from backups in less than a day.
[/Anecdote]

Take a step back, and analyse your needs systematically. (You probably have most of these answers, but they need tying together).
  • What is the value of your data?
  • What threats are you needing to protect against? (Loss of power, fire, vehicle impact, meteor strike, nuclear war?)
  • How important is data continuity? How long a gap can you tolerate?
  • If mains fails, is the data still meaningful?
  • Do you need continuous operation on backup, automatic shutdown, or is manual intervention available (and reliable) 24/7?
  • How long do you need to operate on UPS? (Shutdown only, backup and shutdown, 1hr, 24hr, 7 days?)
  • Do you need backup onsite or offsite?
  • How much data loss (of data that was gathered) can you tolerate? Backup frequency? Real time replication?
  • Is the backup system UPS protected?
  • Can you reduce or eliminate the idiot factor? (See anecdotre above)
  • How quickly can you replace and rebuild the system in the event of hardware failure?
  • Do you need redundancy? (two or three parallel but independent systems)
  • Finally, compare the cost of preventative measures (including capital, running costs, maintenence, planned replacements) with the cost of data loss
Whatever you put in place to reduce your assessed risk to acceptable levels, TEST TEST TEST. Try out the UPS (regularly, immediately after backup). Check the run time (with normal/maximum load). Make sure you can restore a backup. Do not assume that things that passed a test last week/month/year continue in perfect condition.

Hope that helps.
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Re: Is there a cheap and reliable UPS for raspberry pi 3b+?

Sat Mar 09, 2019 12:42 pm

Ernst wrote:
Sat Mar 09, 2019 12:37 pm
Please come back when you have done a POC.
http://www.apcupsd.org/manual/manual.ht ... and-events says
When a major event is generated within apcupsd, control is passed to the script apccontrol normally found in /etc/apcupsd/apccontrol. The event name, and a number of other important parameters are passed to the script.

The major function of the apccontrol script is to perform a shutdown of the system (as well as the killpower operation). In addition, another major task for this script is to notify you by email when certain events such as powerfail occur.
This means I can use /etc/apcupsd/apccontrol to execute ssh shutdown command for my desktop and shut itself down.

It's going to work. I think the more important thing for now is to assess whether I need or want a UPS. Once I decided to buy one, I can research more deeply into it.
davidcoton wrote:
Sat Mar 09, 2019 12:40 pm
Whatever you put in place to reduce your assessed risk to acceptable levels, TEST TEST TEST. Try out the UPS (regularly, immediately after backup). Check the run time (with normal/maximum load). Make sure you can restore a backup. Do not assume that things that passed a test last week/month/year continue in perfect condition.
Thanks. I'll regularly test my infrastructure.

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Re: Is there a cheap and reliable UPS for raspberry pi 3b+?

Sat Mar 09, 2019 12:49 pm

crocket wrote:
Sat Mar 09, 2019 12:42 pm
Ernst wrote:
Sat Mar 09, 2019 12:37 pm
Please come back when you have done a POC.
http://www.apcupsd.org/manual/manual.ht ... and-events says
When a major event is generated within apcupsd, control is passed to the script apccontrol normally found in /etc/apcupsd/apccontrol. The event name, and a number of other important parameters are passed to the script.

The major function of the apccontrol script is to perform a shutdown of the system (as well as the killpower operation). In addition, another major task for this script is to notify you by email when certain events such as powerfail occur.
This means I can use /etc/apcupsd/apccontrol to execute ssh shutdown command for my desktop and shut itself down.

It's going to work. I think the more important thing for now is to assess whether I need or want a UPS. Once I decided to buy one, I can research deeper into it.
davidcoton wrote:
Sat Mar 09, 2019 12:40 pm
Whatever you put in place to reduce your assessed risk to acceptable levels, TEST TEST TEST. Try out the UPS (regularly, immediately after backup). Check the run time (with normal/maximum load). Make sure you can restore a backup. Do not assume that things that passed a test last week/month/year continue in perfect condition.
Thanks. I'll regularly test my infrastructure.
That is a concept, where is the proof ?
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Re: Is there a cheap and reliable UPS for raspberry pi 3b+?

Sat Mar 09, 2019 1:10 pm

Ernst wrote:
Sat Mar 09, 2019 12:49 pm
That is a concept, where is the proof ?
Yes, it's just a concept. I don't want to spend money and produce proof until I become sure that I want or need a UPS. I thought I wanted a UPS, but I'm not sure anymore.

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Re: Is there a cheap and reliable UPS for raspberry pi 3b+?

Sat Mar 09, 2019 1:36 pm

Imperf3kt wrote:
Sat Mar 09, 2019 12:10 am
mahjongg wrote:
Fri Mar 08, 2019 6:35 pm
Even worse, I have to perma-ban people who don't realize this is a family friendly forum..... :twisted: :roll:
I believe this is permaban repeat offenders, is it not. Surely first time offense gets a written warning, second offense gets a potential temp
Well you used a swear word in your reply, which technically makes you a repeat offender. :mrgreen:

but it takes a lot more to perma-ban people, there have been people here who behaved badly for years. :roll:
don't take him as a role model.... :lol:

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Re: Is there a cheap and reliable UPS for raspberry pi 3b+?

Sat Mar 09, 2019 3:47 pm

Ernst wrote:
Sat Mar 09, 2019 12:49 pm
That is a concept, where is the proof ?
That's a slightly fighty response. No-one but you has your setup or exact requirements.

On desktop Linux machines, USB-connected UPSs don't always use apcupsd. On mine, the UPS is monitored as if it were a laptop's internal battery. When I lose power (this is Toronto, we have overhead powerlines, so three nines happens), the computer continues happily until the UPS signals that the battery is critically low. Once that happens, like any laptop, it does its best to shut itself down gracefully. This is on a larger UPS than the BE550G-CN mentioned upthread: this one does regular battery-condition checks and claims to be true sine wave.

There are shortcomings to this approach: what if the load on the UPS suddenly got larger and it shut down? I haven't tested that, and I'm not enough of a masochist to want to. But since there are many more laptop users than UPS users, pretending that the UPS is an internal battery is a helpful analogy for many people.

For my Raspberry Pis I have a bunch of the older versions of the BE550G-CN, kept going through regular off-brand battery replacement. Like CO detectors, UPS batteries will always fail at 02:27 with maximum beepage for minimum sleep. Mine are too old to have the USB connection, so I just use them as ride-through protection with no monitoring. Outages are usually short enough that this isn't a problem (except when there are ice storms). There's a chance that the load from a Raspberry Pi might be a little too small for a UPS's uptime estimate to be useful. This is where testing and tweaking comes in.
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Re: Is there a cheap and reliable UPS for raspberry pi 3b+?

Sat Mar 09, 2019 4:54 pm

scruss wrote:
Sat Mar 09, 2019 3:47 pm
Ernst wrote:
Sat Mar 09, 2019 12:49 pm
That is a concept, where is the proof ?
That's a slightly fighty response.
You may notice that there quite a bit of confusion, it is not just the UPS involved.
I have 32GB SD card, but RPi 3 is in transit from china. I will basically make a ZFS pool and install gentoo on it. It's not very different from doing it for my desktop computer. After all, RPi 3 is just a computer like any other.
The above is part of the OPs concept, but has been lost in confusion.

The use of ZFS snapshots as backup is ... another part of the overall concept.
The road to insanity is paved with static ip addresses

Andyroo

Re: Is there a cheap and reliable UPS for raspberry pi 3b+?

Sat Mar 09, 2019 5:39 pm

Davidcotton is correct - weigh the cost of protection vs cost of downtime and recovery.

How far do you go?
For a business running 24x7 I would not do it on a Pi at home - I would have it hosted in a farm with more than:

1) One WAN connection
2) One power supply with both UPS and generator backup - tested and certificated
3) One set of redundant disks
4) One processor box running under VM HA
5) 24*7 monitoring

If I am really paranoid I would host in to divergent centres often with geographic separation (Derby and Leeds) with TWO suppliers

Cheap enough to rent - simple enough to run. Yes I used to do this for a living running 40+ remote sites at one point.

If you want protection it costs. Only you can work out that value but to give you an idea business continuity specialist say take the down time and allow 5 times the time for recovery PER person in the business. Down time is measured from the last backup NOT when the system fails.

Its a lot better to have frequent and often backups :o

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