Should I split a big (8TB) backup disk into more than one partition, or not?

[David Fletcher]

On Thu, 2020-09-24 at 10:30 +0200, Liam Proven wrote:
> On Mon, 21 Sep 2020 at 11:18, David Fletcher <dave at thefletchers.net> wrote:
> >
> > Myself, I've never used RAID. Everybody must understand that if you
> > have an array of n units of a particular HDD with a known MTBF (FTs)
> > then the MTBF of the array (FTa) is going to be FTa = FTs/n. Plus
> > you've probably got additional hardware to interface to all the drives
> > which will further reduce the MTBF.
> 
> Um. I am not familiar with your notation, but that is not how RAID works, no.
> 
> You appear to be ignoring the R in RAID. The R is the important bit,
> because redundancy is why a RAID has a _longer_ MTBF than any of its
> individual drives.

Yes, I know what the 'R' stands for. My point is, that the more drives
you're running, the higher the probability of one of them failing. If
your RAID is such that it can withstand one failed drive and carry on
then you'd better buy another one and get it in there quick before
another goes down. If I'm wrong about this please say. If you're running
something like a retail site which MUST be up at all times then yes,
throw the money at it and buy lots of RAID.

On the other hand if you're just running a very small setup at home for
yourself, is it worth it? I think not. My experience of doing this over
the last 13 years is that if you look at the failure statistics of
someone who continuously runs thousands of drives of all makes then you
pick something from the manufacturer with the lowest failure rate. This
has resulted for me in a server that runs 24/7 for several years with no
problems. By that time whatever LTS version of Ubuntu Server I'm running
is out of support anyway, so I pull the old drive, replace it with a new
one, install the new OS and restore all data from my backup and carry
on. I have learned in the past to never, ever trash a working system
because then you can always retrieve that important file that somehow
got missed from being backed up! Given that 20.04 replaced 14.04 I most
likely won't need to be concerned about this again until April 2026.