Using unison to sync a copy of the full dokuwiki data on the VPS to a Dropbox folder on my Shack PC, so that I have a backup copy, in the cloud in case of disaster. I'd hate to lose all the work that goes into writing this stuff…

• on the Shack PC create a ~/.unison/dokuwiki.prf file

root = /home/gm4slv/Dropbox/Documents/dokuwiki
root = ssh://gm4slv.org.uk//var/www/html/dokuwiki
sshargs = -C

To account for making the laptop's copy into a git repository I added:

ignore = Path .git

to the laptop config (see Github Repository ) — John Pumford-Green 29/05/22 00:29

• on the VPS server create a similar ~/.unison/dokuwiki.prf file

root = /home/gm4slv/dokuwiki
root = ssh://gm4slv.plus.com:27659/Dropbox/Documents/dokuwiki
sshargs = -C

Run the first time on the Shack PC to download the dokuwiki directory tree from the VPS

unison dokuwiki

gm4slv@laptop:~/.unison $ unison dokuwiki
Unison 2.51.3 (ocaml 4.11.1): Contacting server...
Connected [//gm4slv//var/www/html/dokuwiki -> //laptop//home/gm4slv/Dropbox/Docu                                                                                                 ments/dokuwiki]
Looking for changes
Warning: No archive files were found for these roots, whose canonical names are:
        /home/gm4slv/Dropbox/Documents/dokuwiki
        //gm4slv//var/www/html/dokuwiki
This can happen either
because this is the first time you have synchronized these roots,
or because you have upgraded Unison to a new version with a different
archive format.

Update detection may take a while on this run if the replicas are
large.

Unison will assume that the 'last synchronized state' of both replicas
was completely empty.  This means that any files that are different
will be reported as conflicts, and any files that exist only on one
replica will be judged as new and propagated to the other replica.
If the two replicas are identical, then no changes will be reported.

If you see this message repeatedly, it may be because one of your machines
is getting its address from DHCP, which is causing its host name to change
between synchronizations.  See the documentation for the UNISONLOCALHOSTNAME
environment variable for advice on how to correct this.

Donations to the Unison project are gratefully accepted:
http://www.cis.upenn.edu/~bcpierce/unison


Press return to continue.[<spc>]
  Waiting for changes from server
Reconciling changes

local          gm4slv
         <---- file       .htaccess.dist  [f]
         <---- file       COPYING  [f]
         <---- file       README  [f]
         <---- file       VERSION  [f]
         <---- dir        bin  [f]
         <---- dir        conf  [f]
         <---- dir        data  [f]
         <---- file       doku.php  [f]
         <---- file       feed.php  [f]
         <---- dir        inc  [f]
         <---- file       index.php  [f]
         <---- file       install.php  [f]
         <---- dir        lib  [f]
         <---- dir        vendor  [f]

Proceed with propagating updates? [] y
Propagating updates

........

Everything is downloaded from the VPS and saved in the Dropbox folder, from where it is uploaded to the cloud.

I could automate the process, using various command line switches to automatically “do the right thing” without needing to answer Yes/No questions

unison -auto -batch -silent dokuwiki

and even put it in a cron job, but for now just running it every now and again manually might be enough.

If the VPS version of the dokuwiki ever gets totally screwed up I can restore it by running the same script from the other side and chosing which direction to do the sync in ( shack → VPS )

• on the VPS server

unison dokuwkiki

which will pull the last sync'd version from my backup to my home directory on the VPS ( i.e. not straight to /var/www/html/dokuwiki) from where I can copy it back to the webserver directory.

I can run this command regularly to keep a mirror of the Dropbox backup on the VPS in case I need it later.

(update 28/5/22) I've added it to crontab to run daily at 04:30:

#!/bin/bash
 
unison -batch -auto -silent dokuwiki

crontab:

30 04 * * * /home/gm4slv/bin/dokuwiki_unison.sh >/dev/null 2>&1

I made a new github repository to hold the Dokuwiki folder tree, too. The laptop / Dropbox backup, taken via Unison from the VPS server, is the local repository.

The workflow to keep things backed up:

1. on Shack Laptop
   1. run unison to retrieve the current production copy of the DokuWiki directory tree:

      1.  unison -batch -auto dokuwiki 

      2. there was an error flagged → the .git folder isn't present on the VPS's webserver root but is in the unison backup directory on the laptop. Just ignore it?
      3. I found you can tell unison to ignore the .git folder by adding

         ignore = Path .git

         to the prf config file on laptop — John Pumford-Green 29/05/22 00:30

   2. cd into ~/Dropbox/Documents/dokuwiki
   3. add all files to git

      git add .

   4. commit

      git commit -m "backup"

   5. push to github

      git push

2. on VPS
   1. in home directory, run

      unison -batch dokuwiki

      to pull the dropbox copy back to the VPS

   2. copy the dokuwiki tree to /var/www/html/ (is unison also useful here?) (or rsync Dokuwiki Mirror)
3. in extremis it should be possible to simply clone the github repository instead of using unison

Page Updated : 06/03/25 06:49 GMT