I am still using TrueNAS CORE and AFP shares for my macOS clients. I am looking ahead to a future where I migrate the data on my server to TrueNAS Scale. I am trying to understand what that process will do to my data, and how things will change for my clients.
In the TrueNAS Scale 24.10 (Electric Eel) CORE to SCALE Migrations documentation, there is an article AFP Migration. It says,
…to prevent data corruption that could result from the sidegrade operation, in TrueNAS SCALE, go to Windows (SMB) Shares, select the (three dots icon) for the share, then …select Legacy AFP Compatibility to enable compatibility for AFP shares migrated to SMB shares. Do not select this option if you want a pure SMB share with no AFP relation.
Data corruption? OK, you have my attention.
What does this checkbox do, specifically? How does selecting it or not actually affect what happens during the Core-to-Scale sidegrade operation? Or when the resulting share is enabled, and delivered via SMB?
During a sidegrade, how is data on the TrueNAS filesystem which is in the scope of an AFP share changed? Are there any changes to the data on disk? Does this checkbox affect what changes are made?
On which shares do we do this operation? It says, “to prevent data corruption”. So, we check this box before migrating, correct? That means this checkbox should be present in the TrueNAS CORE UI? And if we do it before migrating, the AFP shares will not yet be SMB shares, so how do we control them in the Windows (SMB) Shares UI? Or, is this something we do after migrating, but before enabling those migrated shares and before clients see their contents?
Does the phrase, “AFP shares migrated to SMB shares”, refer to changes in the configuration settings that control the sharing services, or does it also refer to changes to data in the TrueNAS pool, dataset, or directory delivered by the “shares”?
The UI help text on the Legacy AFP Compatibility checkbox appears to say,
This is not required for …MacOS SMB clients.
This is not clear to me. Any AFP share had MacOS clients in the past — what other clients would use AFP? — and the migrated will now be served to MacOS clients via SMB. Those clients are now “MacOS SMB clients”, right? Does the wording in fact mean, a TrueNAS pool, dataset, or directory which has only ever been delivered to MacOS clients via SMB, never by AFP?
Thanks for helping me understand. If this helps suggest clarifications to the documentation, all the better.