ZFS deduplication questions

[dnar]

Just wondering about how dedup works and have a few questions.

1. Will ZFS dedup existing files when it's enabled for the first time?

2. Once enabled, can you disable later?

3. Am I correct in assuming dedup only works within a dataset?

Many thanks in advance.

[raulfg3]

Will ZFS dedup existing files when it's enabled for the first time?

no, dedup never files only , NOT existing ones.

[dnar]

Cool, I suspected as much. Do you know the performance hit with dedup enabled?

[ku-gew]

Extreme hit. Have you tried a search in Google before asking?

[raulfg3]

sorry, no, I remember from a old article I read time ago, perhaps I'm wrong?

[raulfg3]

I google a bit as you suggest and find this: https://groups.google.com/a/zfsonlinux. ... fBO7IPGL68

[dnar]

Extreme hit. Have you tried a search in Google before asking?

Sorry for asking.

[ku-gew]

Sorry raulgf3, I wasn't criticizing your answer, only the question about dedupe performances, since a simple "zfs dedupe performance hit" gives back a lot of useful results.