pete

@cyclohexane I can only speak from my personal experience having hosted both XMPP and Matrix for friends/family before.

Ran XMPP (eJabberd) for round about 10 years and it never really was a trivial process, neither for me as admin nor for my friends/family with regards to parcipating.
Basically, back then, I had to manually extend eJabberd with a bunch of XEPs (namely push notifications, message carbons and message archive) to increase the useability and user convenience to even stand a chance getting people on board and able to use the system. The client ecosystem was not quite there yet either - Conversations for instance had just come around to shaping up for android, Gajim for cross-platform was pretty fine though.
Let's not talk about E2E encryption either: GPG - not a chance, OMEMO was just coming around as well and was not yet very reliable.

Matrix on the other hand was quite the breakthrough for me as an admin with regards to user acceptance. I do believe that a big part of that comes from the concerted effort to have a unified client (Element) available on any platform - web, fat clilent, mobile client.
By now there's also a ton of cross chat platform bridges which also greatly serves as a "selling point" towards users. And most imporantly, again in my humble opinion, the required technical knowledge barrier for users is just not comparable to XMPP.

Don't get me wrong, I've learned so much as an admin setting up and hosting XMPP and for a short while I even had a PoC going at work to try and advocate the protocol, but in the end Matrix feels like a worthy successor to me.
It allows me to convince "normal users" to use a federated, self-hosted and free chat platform reliably - and that's what mostly matters to me :wink:

Joined up yesterday and still trying to get the hang of where to go now in terms of contributing to the guild. Hopefully I'll get to know the members more the coming days!
Other than that I'm all for helping out with the Expidition to the Gilded Hollow! 💪

what timezone are most on right now?
I'll try to get in touch in-game later tonight. I'm in CEST.

at least weekly mysqlcheck + mysqlddump and some form of periodic off-machine storing of that is something I'll surely take to heart after this lil' fiasco ;-) sound advice, thank you!

Hear hear! You don't own a backup if you've never restored it before. Words to live by both in corporate and self-hosting environments.

Ironically, if I would have had more services running in docker I might not have experienced such a fundamental outage. Since docker services usually tend to spin up their exclusive database engine you kind of "roll the dice" as far as data corruption goes with each docker service individually. Thing is, I don't really believe in bleeding CPU computation cycles by running redundant database services. And since many of my services are already very long-serving they've been set up from source and all funneled towards a single, central and busy database server - thus, if that one experiences sudden outage (for instance power failure) all kinds of corruption and despair can arise. ;-)

Guess I should really look into a small UPS and automated shutdown. On top of better backup management of course! Always the backups.

Excellent choice. I'm running a physical Routerboard and a virtual RouterOS inside my hypervisor for redundancy.
The license for virtual RouterOS is dirt cheap and has more features than you could ever dream of with any of the the big network device manufacturers.
The physical devices are very well designed for their relatively modest price and likewise fully featured. Perfect for any home lab or to play around with IEEE conform protocols.

Life is Strange soundtrack. That is, including all the licensed songs.
Was so good, got me into playing guitar.

You're quite bold - I like it ;-) in all honesty, is your requirement mounting an NFS share? As indicated by @chris it really is designed for the local network.
How about using something more suited like a WebDAV share/mount?

You're right - I missed that detail. From the graphs alone it looks as if a process ate up all still free to claim (cached) memory, then the system stalled possibly thrashing until OOM kill intervened - as indicated by large chunks of RAM being freed. Allocated RAM in red lowering and cached RAM in blue rising again.

I don't see a clear indication that you have too low RAM... RAM should be "used" fully at all times and your "cached" RAM value suggest you still have quite a bunch of RAM that could potentially be consumed by applications when they need it.
I cannot clearly see a swap usage in the graphs - that would be an interesting value to judge the overall stability of the system with regards to fluctuating RAM usage.

However, once you notice the problem again, right after you manage to log in, run a "dmesg -T | grep -i oom" and see if any processes get killed due to temporarily spiking RAM consumption. If you're lucky that command might lend some insight even now still.

Also, what if you run a "top" command for a while, what's the value for "wa" in the second line like? "wa" stands for I/O wait and if that value is anything above 5 it might indicate that your CPU is being bottlenecked by for instance hard disk speed.

Of course you are right, and this should be noted.
But if you so happen to have Calibre already running via for instance your desktop installation you, may also "take advantage your pre-existing Calibre database" in Calibre-Web ;-)