On 06/02/12 14:20, Trent W. Buck wrote:
Toby Corkindale wrote:
I'm giving btrfs another go now; pity about losing the block-based dedup (which is great when you have a lot of virtual machine images)
Um, cp --reflink=yes host0.img host1.img.
You don't get *de*dupping (yet), but if you explicitly tell btrfs that the new file should start off with the same blocks as the old file, they'll be non-dupped to begin with.
OK, granted, over time they will drift apart and dedupped would have helped if both VMs made the same changes to the same virtual blocks, but AFAICT --reflink solves the first 90% of the problem.
Ah, it might solve 90% of your problem, but it doesn't for most people, where a VM image is created from scratch via an ISO image of an installer, and then the VM has lots of patches and upgrades applied over time. But thanks for pointing it out, as it might be useful info for someone. Cheers, Toby