backup v rsync

[Jeff Abrahamson]

I've been migrating from a dovecot 2.2.22 instance to a dovecot 2.3.7.2 
instance.
(Said differently, from an ubuntu 16.04 host to a 20.04 host.) It's a 
tiny site:
only a handful of users actually had to migrate, most either died on the 
old one
or were born on the new one.  The main user in need of migration was me.

After fiddling with dsync and not getting it working, I threw in the 
towel.  This
is a migration I had to do once for precisely one user.  I had been 
using the old
host exclusively, so it was easy to shut down both dovecot instances the 
time it
took me to rsync my data from one to the other.  Now that seems to work, 
almost.
Mail is being delivered to my inbox, anyway.  Most other folders are 
looking
inaccessible to my mail client (thunderbird, for this test).

The main difference between the two servers, aside from the above, is a 
switch from

     mail_location = maildir:~/Maildir

to

     mail_home = /var/mail/vmail/%d/%n
     mail_location = maildir:/var/mail/vmail/%d/%n/mail:LAYOUT=fs
     mail_privileged_group = mail

I corrected permissions and ownership when I copied the data.

Now I think the problem is that LAYOUT=fs means that I should have a 
slightly different
folder hierarchy now.  The question is how best to fix this.

I have things like this

     .Archives.2020
     .Archives.2020/new
     .Archives.2020/tmp
     .Archives.2020/cur

when I think I should have things like this

     Archives
     Archives/2021
     Archives/2021/new
     Archives/2021/tmp
     Archives/2021/cur

And, again, this is one-off, so a manual fix seems most appropriate.  
I'm quite tempted
simply to shut down the dovecot instance for a minute at a quiet moment 
(mail retries...)
and rename directories as indicated above.  I only have to rename five 
directories.

Having gotten myself in a bit of a muddle on this, I thought perhaps a 
reality check that
I'm not about to make it worse would be appropriate.

Many thanks.

-- 
Jeff Abrahamson
+33 6 24 40 01 57
+44 7920 594 255
https://www.p27.eu/jeff/
https://www.mobilitains.fr/