Hacker News Reader

Comment by betaby | Hacker News Reader

But RAID-6 is the closest approximation to raid-z2 from ZFS! And raid-z2 is stable for a decade+. Indeed btrfs works just fine on my laptop. My point is that Linux lacks ZFS-like fs for large multi disc setups.

View on HN

Seriously for the people who take filesystems seriously and have strong preferences... Multi disk might be important.

BTRFS does have stable, usable multi-disk support. The RAID 0, 1, and 10 modes are fine. I've been using BTRFS RAID1 for over a decade and across numerous disk failures. It's by far the best solution for building a durable array on my home server stuffed full of a random assortment of disks—ZFS will never have the flexibility to be useful with mismatched capacities like this. It's only the parity RAID modes that BTRFS lacks, and that's a real disadvantage but is hardly the whole story.

That’s nice and all, but I have five disks in my server. I want the 6 mode.

In practice RAIDZ2 works great.

In the case of five disks of the same capacity, RAID6 or RAIDZ2 only gets you 20% more capacity than btrfs RAID1. That's not exactly a huge disparity, usually not enough to be a show-stopper on its own. There are plenty of scenarios where the features ZFS has which btrfs lacks are more important than the features that btrfs has which ZFS lacks. My point is simply that btrfs RAID1 has its uses and shouldn't be dismissed out of hand.

This is missing one of the finer points of redundancy: With 4 disks, losing two of them could take out a RAID-10 (both halves of a stripe component), but losing two cannot take out a RAID-6.

The fact that btrfs isn't stable after 15+ years for parity setups is, IMO, unreasonable.

Reply on news.ycombinator.com