Re: write corruption due to bio cloning on raid5/6

["Janos Toth F." <toth.f.janos@gmail.com>]

Reply to the TL;DR part, so TL;DR marker again...

Well, I live on the other extreme now. I want as few filesystems as
possible and viable (it's obviously impossible to have a real backup
within the same fs and/or device and with the current
size/performance/price differences between HDD and SSD, it's evident
to separate the "small and fast" from the "big and slow" storage but
other than that...). I always believed (even before I got a real grasp
on these things and could explain my view or argue about this)
"subvolumes" (in a general sense but let's use this word here) should
reside below filesystems (and be totally optional) and filesystems
should spread over a whole disk or(md- or hardware) RAID volume
(forget the MSDOS partitions) and even these ZFS/Brtfs style
subvolumes should be used sparingly (only when you really have a good
enough reason to create a subvolume, although it doesn't matter nearly
as much with subvolumes than it does with partitions).

I remember the days when I thought it's important to create separate
partitions for different kinds of data (10+ years ago when I was aware
I didn't have the experience to deviate from common general
teachings). I remember all the pain of randomly running out of space
on any and all filesystems and eventually mixing the various kinds of
data on every theoretically-segregated filesystems (wherever I found
free space), causing a nightmare of broken sorting system (like a
library after a tornado) and then all the horror of my first russian
rulett like experiences of resizing partitions and filesystem to make
the segregation decent again. And I saw much worse on other peoples's
machines. At one point, I decided to create as few partitions as
possible (and I really like the idea of zero partitions, I don't miss
MSDOS).
I still get shivers if I need to resize a filesystems due to the
memories of those early tragic experiences when I never won the
lottery on the "trial and error" runs but lost filesystems with both
hands and learned what wild-spread silent corruption is and how you
can refresh your backups with corrupted copies...). Let's not take me
back to those early days, please. I don't want to live in a cave
anymore. Thank you modern filesystems (and their authors). :)

And on that note... Assuming I had interference problems, it was
caused by my human mistake/negligence. I can always make similar or
bigger human mistakes, independent of disk-level segregation. (For
example, no amount of partitions will save any data if I accidentally
wipe the entire drive with DD, or if I have it security-locked by the
controller and loose the passwords, etc...)