Hi, > On Mar 27, 2017, at 4:48 PM, Roman Mamedov wrote: > > On Mon, 27 Mar 2017 15:20:37 +0200 > Christian Theune wrote: > >> (Background info: we’re migrating large volumes from btrfs to xfs and can >> only do this step by step: copying some data, shrinking the btrfs volume, >> extending the xfs volume, rinse repeat. If someone should have any >> suggestions to speed this up and not having to think in terms of _months_ >> then I’m all ears.) > > I would only suggest that you reconsider XFS. You can't shrink XFS, therefore > you won't have the flexibility to migrate in the same way to anything better > that comes along in the future (ZFS perhaps? or even Bcachefs?). XFS does not > perform that much better over Ext4, and very importantly, Ext4 can be shrunk. That is true. However, we do have moved the expected feature set of the filesystem (i.e. cow) down to “store files safely and reliably” and we’ve seen too much breakage with ext4 in the past. Of course “persistence means you’ll have to say I’m sorry” and thus with either choice we may be faced with some issue in the future that we might have circumvented with another solution and yes flexibility is worth a great deal. We’ve run XFS and ext4 on different (large and small) workloads in the last 2 years and I have to say I’m much more happy about XFS even with the shrinking limitation. To us ext4 is prohibitive with it’s fsck performance and we do like the tight error checking in XFS. Thanks for the reminder though - especially in the public archive making this tradeoff with flexibility known is wise to communicate. :-) Hugs, Christian -- Christian Theune · ct@flyingcircus.io · +49 345 219401 0 Flying Circus Internet Operations GmbH · http://flyingcircus.io Forsterstraße 29 · 06112 Halle (Saale) · Deutschland HR Stendal HRB 21169 · Geschäftsführer: Christian. Theune, Christian. Zagrodnick