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Domoticz fail-over construction / redundant setup?

Posted: Sunday 31 January 2021 15:25
by Sjonnie2017
Hi All,

Since my entire house is now somewhat controlled by Domoticz I realize that if some part of my installation fails I have a serious problem (moving around the house in the dark and getting my roller shutters up so i can see the light of day :mrgreen: ).

I use a Raspberry Pi for Domoticz combined with a Conbee II stick. The Pi is backed up daily on an external SSD. So in case of failure I can always restore the Pi (if it isn't broken) but it is time consuming to say the least and rather a pain in the b*tt if it's dark ;)

If I could make a suggestion I would like Domoticz to be able to have a redundant (spare) device that would take over in case of failure. The spare device could monitor the presence of the primary Domoticz (heartbeat) and if the primary device is not available activate the second Domoticz installation and take over control. This does not have to be fully automated but with as little an effort as possible (better for the WAF I think).

If this is possible I would have to buy spare hardware of course and I would also have to restore the Conbee database for the fail-over hardware to work but I think that would only take a matter of minutes as opposed to restoring to a new Pi (which would be done eventually of course).

Would this be feasible? Or is this possible already (haven't been able to find information in the wiki).

TIA

Greetz,

Sjonnie

Re: Domoticz fail-over construction / redundant setup?

Posted: Sunday 31 January 2021 17:15
by brommetje
Hi @sjonnie

Maybe you can use HA Cluster with DRDB (or just DRDB) to replicate the disk running Domoticz between two PI’s.
Or put Domoticz on shared storage for example nfs/synology.

The only thing you have to do if you have problems move your USB devices (sticks) to the other PI.

Martin

Re: Domoticz fail-over construction / redundant setup?

Posted: Sunday 31 January 2021 17:54
by Sjonnie2017
Hi Martin,

Thanks for your reply and suggestion.

DRDB looks not that simple on a Pi if I look at this: https://www.golinuxcloud.com/drbd-tutor ... -centos-8/ I haven't been able to find a link to explain DRDB on a Pi but I will have another look. If you would be able to share some links I would be grateful.

Greetz,

Sjonnie

Re: Domoticz fail-over construction / redundant setup?

Posted: Tuesday 24 August 2021 7:06
by renerene
bump.

Looking for the same solution here.
I would be happy to buy another rpi hardware set and sleep better knowing I can swotch withon a minute to another system.

Re: Domoticz fail-over construction / redundant setup?

Posted: Tuesday 24 August 2021 19:27
by solarboy
I aim to have a copy of all my hardware and software so I can boot a spare pi with the USB controllers and spare preloaded SSD (cloned), stop Domoticz, upload the latest backup from by NAS and check all is functioning, with the option to replace my Zwave stick for a spare, already pre-loaded with a backup of the old stick. Also spare Zigbee and RFXcom devices.

Once I have gathered all the hardware I'll give it a test, would be worth swapping from one set-up to another once a month or so to ensure a working system is always reasonably up to date and available.

Re: Domoticz fail-over construction / redundant setup?

Posted: Tuesday 24 August 2021 20:06
by waltervl
It is always a question of risc analysis:
What would probably fails most and what is the impact on current operation and effort to repair. For example:
SD-card
USB Zigbee/Zwave/RFXCOM stick
Raspberry Pi
Router
NAS
etc

And then act on that.
SD card to fail, chance is high, impact is high, effort to repair is high (complete new installation). So perhaps switch to a setup without SD using a SSD or NAS, or keep a spare prepaired SD card ready (takes effort to maintain by discipline or script).
Never heared of a broken USB Zigbee/Zwave/RFXCOM stick yet so possible no need to have a backup.
A broken raspberry Pi, chance is low and next day delivery for a new one (in the Netherlands)
etc
But you all have your own setup so your own analysis to do....

Re: Domoticz fail-over construction / redundant setup?

Posted: Tuesday 24 August 2021 20:20
by solarboy
The Zwave mesh itself is vulnerable to broken hardware, for example a failed node, I have about 15% of nodes die within 2 years and while I wait for a new one the whole mesh could be down leading to hours of reconfiguration, including, excluding, opening up wall boxes to access devices. I am sure we have all been there.