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.

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 ;-)

Take a look at Calibre-Web (github.com/janeczku/calibre-we…) which I’ve been using for what you ask for quite a while now. As the name suggests it can also take advantage of a pre-existing Calibre eBook Database.