<issue_start><issue_comment>Title: Architecture Decision #3: Preservation
username_0: 
<issue_comment>username_1: I think we should say something about how we are going to check fixity; I think that discussion / those decisions inform and are informed by this -- should that be a separate ADR or part of this one?
<issue_comment>username_0: We could talk about that here, but I don't think we'll know what exactly to say until we try the options and see what works
<issue_comment>username_1: @username_0 maybe we could at least add in something about how checksum will be calculated? You said something in channel about excluding the FileMetadata node.
<issue_comment>username_2: I thought about including fixity checking in my ADR draft, but decided it could be in a separate ADR instead.  But I agree that we should document both sides of the process, whether it's in this ADR or a followup.
<issue_comment>username_3: I'm not sure where to comment this so apologies if this is the wrong place, but the resulting preservation design document sounds a lot like OCFL. Have you considered looking at it? https://ocfl.io
<issue_comment>username_0: @username_3 Could you make an issue? We did look at OCFL, but I think the discussion deserves something not-closed, so we don't lose track of it.
<issue_comment>username_3: @username_0 #2884