> If I do that with a linux/solaris/mdadm/zfs/btrfs/whatever, and it fails, who will be the one blamed for the failure? Me of course.
So don't create a 16-drive RAID5 at all.
> If i select a propper raid setup, and it still failes, it's better if it fails on an IBM than on my duct-tape linux/mdadm/zfs/btrfs/whatever solution, because again, I personally can say, that i did what the vendor (IBM) recommended in their brochure, and their solution failed.
But you're the one who chose the vendor, and evaluated their solution, and accepted it. So you're still fired.
> Either way, you have to restore from backup.
The point is there's a third option. Use a level of redundancy appropriate to the importance of the system, and then it doesn't fail to begin with and it isn't necessary to divert blame. Meanwhile you get to show your boss how you saved the company millions of dollars.
> And if there is some random bug (eg. kernel oops when mounting volume), there's IBM support on the call. Working with standard options, means standard, well-known bugs, and that means that support can help fix them.
Which you can still get for linux/solaris/mdadm/zfs/btrfs/whatever from a variety of vendors if you really want it. But because they're generic technologies, this also means you can get that support from multiple competing providers (so the cost is lower), including per-incident support once something happens that requires it instead of having to buy a support contract you may not ever need.
Which you generally won't need, because the likes of mdadm are more widely used (and so better tested) than any individual vendor's proprietary hardware RAID solution, and can also recover more easily from things like controller failures because the replacement controller needs no state and is not required to match in firmware version or even model.