SUSE reaffirms support for Btrfs

Posted Aug 29, 2017 5:40 UTC (Tue) by kreijack (guest, #43513)
In reply to: SUSE reaffirms support for Btrfs by thoughtpolice
Parent article: SUSE reaffirms support for Btrfs

> Also, bcachefs is as much a clone of btrfs as btrfs is of ZFS -- they're all "next-gen" filesystems, but naturally they all have different
> points in the design space. For example, it features very efficient metadata overhead, in some cases leaving to order-of-magnitude
> improvements over others (because metadata can effectively fit in your L2 cache -- a user on IRC once reported bcachefs vs
> <anything else> was something like 500,000 files/s vs < 70,000 files/s, in a directory with a few hundred thousand files.) bcachefs also
> has very good tail latency compared to most systems because it doesn't block necessarily.[1]

Due to the fact that the snapshot feature is missing, it is normal that bcachefs has better performance. The snapshot capability has a big impact on the performance (e.g. each block have a reference counter which has to be update, when a block is created, changed or deleted). I think that we could discuss about the bcachefs performance after it has a comparable set of feature.

SUSE reaffirms support for Btrfs

Posted Aug 30, 2017 0:33 UTC (Wed) by koverstreet (✭ supporter ✭, #4296) [Link] (1 responses)

That's just silly - you're assuming one approach to implementing snapshots, which has little to do with how they're going to be implemented in bcachefs.

Anyways, snapshots aren't the only feature users care about. At this rate, bcachefs is going to have proper working RAID before btrfs.

SUSE reaffirms support for Btrfs

Posted Aug 30, 2017 16:59 UTC (Wed) by kreijack (guest, #43513) [Link]

> That's just silly - you're assuming one approach to implementing snapshots, which has little to do with
> how they're going to be implemented in bcachefs.

You are right when you say that I don't know the bcachefs internal, however it still not correct to compare the speed of filesystems when the features aren't comparable.

Anyway I am curious how the snapshot are implemented in bcachefs. Could you share with us more details ? How is scalable the bcachefs solution (btrfs behave well with ~100 snapshots, and with some limits is tolerant with 1000 snapshots)

> Anyways, snapshots aren't the only feature users care about.
> At this rate, bcachefs is going to have proper working RAID before btrfs.

I can't comment about prediction. I hope that bcachefs will be a good filesystem.
Anyway on of the biggest problem in BTRFS is the huge number of features and their combinations. The most difficult thing is verify that BTRFS behave "not so bad" in every combination.