Going big with TCP packets

But a four-drive raid-10 is actually far more dangerous to your data ... A raid 6 will survive a double disk failure. A double failure on a raid 10 has - if I've got my maths right - a 30% chance of trashing your array.

md-raid-6 doesn't (if configured that way) have a write hole any more.

> Btrfs raid6 is said to be "unsafe" but in reality, it is probably safer than mdraid raid6 or a raid controller's raid6.

I hate to say it, but I happen to KNOW that btrfs raid6 *IS* unsafe. A lot LESS safe than md-raid-6. It'll find problems better, but it's far more likely that those problems will have trashed your data. Trust me on that ...

At the end of the day, different raids have different properties. And most of them have their flaws. Unfortunately, at the moment btrfs parity raid is more flaw and promise than reality.

Oh - and my setup - which I admit chews up disk - is 3-disk raid-5 with spare, over dm-integrity and under lvm. Okay, it'll only survive one disk failure, but it will also survive corruption, just like btrfs. But each level of protection has its own dedicated layer - the Unix "do one thing and do it well". Btrfs tries to do everything - which does have many advantages - but unfortunately it's a "jack of all trades, crap at some of them", one of which unfortunately is parity raid ...

And while I don't know whether my layers support trim, if they do, btrfs has no advantage over me on time taken to rebuild/recover an array. Btrfs knows what part of the disk is use, but so does any logical/physical device that supports trim ...

Cheers,
Wol