What does "mediaserver" mean to you? Synology are good for storage but not so great for more CPU intensive stuff, plus of course they're not freely upgradeable and you're tied to their OS.

If you're comfortable building your own PC you can install Unraid or TrueNAS which will give you an easy to use admin interface and the ability to use/upgrade with off-the-shelf components. /r/buildapc can probably help with that.

If you're also comfortable with Linux you can design your own fine-grained approach to the OS and the apps on it, /r/selfhosted can probably help with that.

SSD's are getting there in $$$/TB but have a bit more to go to catch up to HDDs.

Your approach of having multiple backup drives is sound. Having everything in one place means all eggs in one basket. Keep that in mind when you reorganize your data.

Same, except I also use Scrutiny to flag drives for my attention. It makes educated guesses for a pass/fail mark, using analysis of vendor-specific interpretations of SMART values, matched against the failure thresholds from the BackBlaze survey. It can tell you things like "the current value for the Command Timeout attribute for this drive falls into the 1-10% bracket of probability of failure according to BackBlaze".

It helps me to plan ahead. If for example I have 3 drives that Scrutiny says "smell funny" it would be nice if I had 2-3 spares on hand rather than just 1. Or if two of those drives happen to be together in a 2-pair mirror perhaps I can swap one somewhere else.

Yeah I was under the impression these two attributes vary so wildly between vendors that they're basically void of meaning by now.

(not OP) What's an example of a good quality SATA power splitter? I have something like this.

I'll just leave this here: https://github.com/jmbannon/ytdl-sub

It's a tool that watches YouTube channels or playlists, downloads everything, and prepares them so they appear directly in players like Plex, Jellyfin, Kodi etc. Basically the equivalent of the *arr stack for YouTube.

How much of that data would mean the end of the world if it were lost?

For some of that data (perhaps Jellyfin containers, those test VMs) you may not need RAID at all.

Sellers usually balk at running a long test unfortunately. Sometimes they do it proactively and show you SMART data with a recent long test log already included but it's very seldom.

Many sellers aren't technically savvy and it's the first time they hear about Hard Disk Sentinel, they give you pics of the computer monitor taken with their phone etc. I consider it a win if they can manage to show you the complete SMART attributes.

BTW those aren't actual PHP files, they're most likely HTML. PHP is what they're called when they're code on the live website but the tools that make these archives only copy a dump of the webpages. It should have renamed them but apparently didn't. You'll have to do the renaming instead in order to open them. It's also extremely likely that the links between the forum pages are also ending in .php and won't work (the tool was also supposed to have converted the links inside the files).

httrack.com is one option to mirror the site for your personal use. Unfortunately there's no way to tell how long it would take and how large it would end up being.

I wonder also about the legality of then uploading the site to another domain

That would most likely be a breach of copyright.

What filesystem does the original HDD use?

Not understanding how you will set up the vdev without losing data.

I'm confused, I haven't used TrueNAS before, can it only work with one pool at a time or what? Why would it lose data?

Can't OP connect the two new drives as a separate RAIDz1 pool, copy the data, then wipe the original drive/pool?