Re: NFS exports of ZFS snapshots broken

Rick Macklem <rick.macklem_at_gmail.com> wrote on
Date: Sat, 18 Nov 2023 16:09:34 UTC:

> . . .
> I will try and get a test setup going here, which leads me to..
> how do I create a ZFS snapshot? (I do have a simple ZFS pool running
> on a test machine, but I've never done a snapshot.)
> . . .

There is: "man zfs-snapshot" for "zfs snapshot" commands.

I mention this in part because it references also using "zfs promote"
to swap around the status of what is a snapshot vs. what is not.
There is also the man page, accessible via: "man zfs-promote" . 
man zfs-snapshot also mentions destroying snapshots via "zfs destroy".

The man pages have examples, such as:

   Example 1: Creating a ZFS Snapshot
     The following command creates a snapshot named yesterday.  This snapshot
     is mounted on demand in the .zfs/snapshot directory at the root of the
     pool/home/bob file system.
           # zfs snapshot pool/home/bob@yesterday

Example 3 involves all 3 operations (snapshot, promote, destroy) that
I've referenced:

   Example 3: Promoting a ZFS Clone
     The following commands illustrate how to test out changes to a file
     system, and then replace the original file system with the changed one,
     using clones, clone promotion, and renaming:
           # zfs create pool/project/production
             populate /pool/project/production with data
           # zfs snapshot pool/project/production@today
           # zfs clone pool/project/production@today pool/project/beta
             make changes to /pool/project/beta and test them
           # zfs promote pool/project/beta
           # zfs rename pool/project/production pool/project/legacy
           # zfs rename pool/project/beta pool/project/production
             once the legacy version is no longer needed, it can be destroyed
           # zfs destroy pool/project/legacy

The description of "zfs promote" is:

DESCRIPTION
     The zfs promote command makes it possible to destroy the dataset that the
     clone was created from.  The clone parent-child dependency relationship
     is reversed, so that the origin dataset becomes a clone of the specified
     dataset.

     The snapshot that was cloned, and any snapshots previous to this
     snapshot, are now owned by the promoted clone.  The space they use moves
     from the origin dataset to the promoted clone, so enough space must be
     available to accommodate these snapshots.  No new space is consumed by
     this operation, but the space accounting is adjusted.  The promoted clone
     must not have any conflicting snapshot names of its own.  The zfs rename
     subcommand can be used to rename any conflicting snapshots.


===
Mark Millard
marklmi at yahoo.com