Sanity Check: Swapping storages (encryption and erasure coding)

[87aa841a6fec03dd1ad6]

I have two unencrypted, bit-identical storages with erasure coding – call them A and B

I’d like to (1) encrypt them and (2) change the erasure coding ratio

My plan is:

1. Remove/reset storage B and re-init as encrypted and copy-compatible with A, with the new erasure coding
2. Copy from A to B
3. Verify B works with a test restore

Once verified, repeat in reverse with bit-identical:

1. Remove/reset storage A and re-init as encrypted (with the same password) and bit-identical copy-compatible with B, with the new erasure coding
2. Copy from B to A
3. Verify A works with a test restore

Which should (I hope) give me two encrypted, bit-identical storages with the new erasure coding ratio.

Any obvious flaws in that plan?

[gchen]

Yes, this should work. I don’t see anything wrong.

[87aa841a6fec03dd1ad6]

One difficulty I encountered: I couldn’t see where to set bit-identical in the WebGUI.
Possible I missed it.

[Droolio]

@87aa841a6fec03dd1ad6

I couldn’t see where to set bit-identical in the WebGUI.

You’d have to create the -bit-identical storage with CLI first. Once initialised you can add and work with it via GUI.

@gchen

Yes, this should work. I don’t see anything wrong.

Incidentally @gchen, what’s the ramifications of having two -bit-identical storages - one with erasure coding and one without? Or one with a different erasure coding ratio.

Are the chunks independently interchangeable either manually or with third party tool i.e. rsync?

[87aa841a6fec03dd1ad6]

@Droolio

You’d have to create the -bit-identical storage with CLI first. Once initialised you can add and work with it via GUI.

Yeah, that’s what I did.
It wasn’t difficult but less intuitive than a checkbox.

@Droolio

what’s the ramifications of having two -bit-identical storages - one with erasure coding and one without

In testing I saw the CLI lets you do it, at least with two different erasure-coding ratios. No warning or error but I can’t imagine it works.

[gchen]

@Droolio

Incidentally @gchen, what’s the ramifications of having two -bit-identical storages - one with erasure coding and one without? Or one with a different erasure coding ratio.

-bit-identical doesn’t override the erasure coding ratio, so you can have two bit-identical storages with different erasure coding ratios. It is still ok to copy chunks from one to the other with rsync or rclone, but then the copied chunks will have a different erasure coding ratio with others.