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A comment on OpenZFS deduplication is good now and you shouldn't use it. Parent comment

Re:OpenZFS deduplication is good now and you shouldn't use it by magicalhippo on Wednesday October 30, 2024 @06:40PM (#42001299)
> and fixup the block pointers

That's why. Due to reasons[1], ZFS does not have the capability to rewrite block pointers. It's been a long requested feature[2] as it would also allow for defragmentation.

I've been thinking this could be solved using block pointer indirection, like virtual memory, at the cost of a bit of speed.

But I'm by no means a ZFS developer, so there's surely something I'm missing.

[1]: http://eworldproblems.mbaynton.com/posts/2014/zfs-block-poin...

[2]: https://github.com/openzfs/zfs/issues/3582

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Re:OpenZFS deduplication is good now and you shouldn't use it by phongn on Wednesday October 30, 2024 @07:25PM (#42001699)
It looks like they’re playing more with indirection features now (created for vdev removal) for other features. One of the recent summit hackathons sketched out using indirect vdevs to perform rebalancing.

Once you get a lot of snapshots, though, the indirection costs start to rise.

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