High water vs Fill up

[MacRaid]

Hey guys, me again the noob. I'm starting my UnRaid and thinking about how to configure my shares I can see a lot of options, I kind of got the hang of the "Split Levels" logic but now trying to decide if I should use High Water or Fill Up. The main purpose is to have my media, family stuff, and documents of sorts and also use Plex. So besides the 4tb parity drive I have 2 4tb disks (intent to use for media) and one 1tb drive for the family stuff. 

I want to spin my disks as less as I can and also avoid the ~5sec. posible delay for one episode to the other, among other things. 

So what do you guys think between High Water vs Fill Up methods?

Thanks in advance...

[testdasi]

High Water (in fact I prefer Most Free).

A major reason for Unraid array in consumer use cases (as opposed to a RAID solution such as ZFS) is that having more failed drive than parity will not cause you to lose all your data (except for when all data drives failed, which I would consider catastrophic and thus can only be mitigated with a backup).

 

If you use Fill Up and let's say you have only 4TB of data, all of it would be on 1 drive. That means if your parity and that drive die, you will lose everything (because the other 4TB is blank). With High Water, at least you still have some data left (as it should be split across both drives).

Of course, you could be lucky and lose parity + empty drive but then if you plan on being lucky then why not just run without parity to begin with right?

 

The only reason to use Fill Up in my mind is that all the data on the drives are easily replaceable and/or does not cost much if lost. Archival storage is a good example that probably can use Fill Up.

[MacRaid]

What are the chances of loosing 2 drives in a UnRaid? On top of it what are the chances of those two drives being parity + most fill drive? Thanks for your input, I still think fill up will be better in an ideal world but you do have a point on Murphy's law there. I'll wait to see more opinions otherwise I'll go for the High Water with the Split Level rules. How's that?

[Cpt. Chaz]

Limetech description: "The goal of High-water is to write as much data as possible to each disk (in order to minimize how often disks need to be spun up)"

 

in addition to everything @testdasi said, this seems to be your best use case.

[MacRaid]

I would understand it differently, (if one disk is written first to almost full before moving to the other then disk 2, 3, etc will not spin at all, in Fill Up) unless you're talking about a good combination of high water and split levels setting. But I think you guys have way more experience than me, so I'll go with that. Thanks again...