Bug 248545

Summary:	zfs: add possibility to create an initial send stream without intervening snapshots
Product:	Base System	Reporter:	Martin Birgmeier <d8zNeCFG>
Component:	bin	Assignee:	freebsd-fs (Nobody) <fs>
Status:	New ---
Severity:	Affects Only Me
Priority:	---
Version:	12.1-RELEASE
Hardware:	Any
OS:	Any

Description Martin Birgmeier 2020-08-09 07:24:24 UTC

Scenario:
- FreeBSD 12.1-RELEASE-p6
- Using "zfs send" to create backups
- Using "-R" flag to create backups of zfs filesystem hierarchies
- Using "-I" or "-i" to create incremental backups
- For these backups, specifically named snapshots are used which are created using "zfs snapshot -r <top filesystem>" (the <top filesystem> is not necessarily a complete pool but can be a subset of a pool).
- There are other (intervening) snapshots that are irrelevant for backup purposes.

Result:
1. It is possible to create a full recursive backup stream (similar to a level 0 dump) using "zfs send -R ...", including all intervening snapshots, even those irrelevant for backup purposes.
2. It is NOT possible to create a full recursive backup stream using "zfs send -R ...", excluding all intervening snapshots.
3. It is possible to create an incremental recursive backup stream using "zfs send -R -I ...", including all intervening snapshots.
4. It is possible to create an incremental recursive backup stream using "zfs send -R -i ...", excluding all intervening snapshots.

Expected result:
It should be possible to create a full recursive backup stream WITHOUT the intervening snapshots (case 2. above).

-- Martin

Comment 1 Martin Birgmeier 2020-08-09 07:27:44 UTC

p.s. I am wondering how "zfs send -R -i ..." works in the presence of clones using a snapshot in between the -i <snapshot> and the target <snapshot>.