I decided to not try the “partition resizing” approach because it seems that expanding next the Volume to use the free space on the partition could be difficult (if possible at all). I will for sure try that idea later with dummy data. But for now, I wanted a peace-of-mind-solution. So, I did:

1. Create a Virtual Synology (a DS3612xs with DSM 5.0-4528) with enough space,
2. Enable the Network Backup Service on that DS3612xs
3. Clean-up as much as possible on the DS713+ (DSM 5.0-4528 update 1)
   1. Disabled the camera in Surveillance Station and  deleting all the recordings
   2. Stopping Plex, Video Station, Audio Station and Photo Station
   3. Deleting all the movies from \\<DiskStation>\video (As those are anyway backuped on my main server)
   4. Deleting all the musics from \\<DiskStation>\music (As those are anyway backuped on my main server)
   5. Keeping however the photos to not loose albums’ settings and thumbnails (as those would require days to be recreated!)
4. Backup as much as possibly from the DS713+
   1. Using the native “Backup & Replication” feature, but also
   2. “Exporting” the Configuration of the “Surveillance Station” and Copying the extra licences (not the default one)
   3. “Exporting” all the complete zones’ settings from the “DNS Server”
   4. Taking note of the information not backuped:
      1. “QuickConnect”
      2. “External Access”
      3. “Network”
      4. “Security”
      5. “Notification”
      6. “Application Portal alias”
   5. Taking note of:
      1. All the Packages installed:
      2. The custom “Package sources” configured in the settings of the Package Center
   6. Backuping Wordpress
      1. Stopping first WordPress
      2. Taking a Backup of the database wordpressblog via a full “Export” with phpMyAdmin
   7. In addition, to be 100% safe,I also took a full copy of
      1. the Plex’s configuration & settings: \\<DiskStation>\Plex\Library\Application Support\Plex Media Server
      2. the WordPress installtion: \\<DiskStation>\web\wordpress
      3. All my “customized” stuff
5. Replace the 2 x 2TB with the 2 x 3TB in the DS713+
6. Reinstall DSM 5.0 on the DS713+ with the same name and admin’s password as previously
7. I reinstalled WordPress, Plex, DNS Server and PhotoStation, but I did not configure them and stopped them! (Actually, I don’t know yet if installing them before the restore was required… — to be checked).
8. Enable the Telnet Service in “Terminal & SNMP”
9. Restore manually the information for
   1. “QuickConnect”
   2. “External Access”
   3. “Network”
   4. “Security”
   5. “Notification”
10. Restore the Backup made on the DS3612xs. It included:
    1. All the Shared Folders selected to be backuped
       1. Shared Folders recreated when installing a Packages are renamed!
    2. The “File Services” settings
    3. The “Users”
    4. The “Groups”
    5. (I don’t use the Directory Services)
    6. The “Regional Options”
    7. The “Task Scheduler”
    8. The “Application Portal” alias
11. Reinstall the other Packages.
12. Import manually the DNS zones exported previously (via “Create” > “Import zone”).
13. Fix issues with “Surveillance Station” if any.
    1. I had to delete the camera restored with the Backup in “Surveillance Station” (weird as I successfully restored such backups in the past…)
    2. Add manually my extra licences
    3. Import manually the Configuration settings I exported previously.
14. Restore manually the database of WordPress via phpMyAdmin and start next WordPress. It should not prompt you anymore to configure it.
15. Check that the expected content has been restore in the various Shared Folders: photo, Plex (music and video if not cleaned-up), etc…
16. Delete all Plex’s plugins (hidden folder \\<DiskStation>\Plex\Library\Application Support\Plex Media Server\Plug-ins). They will be reinstalled automatically when you will start Plex. I have indeed noticed that various features do not run fine anymore in the Administration site otherwise. Ex.: choose language when editing libraries or fixing incorrect match, choosing providers, etc…
17. Start all Packages currently stopped.

1. Take the latest Boot Image iso available to start a “DSM” in a VMWare (Nanoboot-5.0.3.2 DSM 5.0-4528 x64) here.
2. Take next the latest DSM pat Image (DSM 5.0-4528) here.
3. Get the Synology Assistant from here and install it.
4. Use VMWare Workstation 10 to create a new VM (You may create a Shared one to be able to run it remotely if you want):
   1. Create a “Custom (Advanced)” virtual machine
   2. Linux, version “Other Linux 2.6.x kernel 64-bit”
   3. With 1 processor, 2 cores
   4. 1024MB Memory
   5. Using a Bridged network
   6. LSI Logic Controller
   7. SCSI Disk Type
   8. And a large new virtual disk fully allocated (for performance reason)
5. Instead of starting the new machine immediately, edit the settings: the CD/DVD must be changed to use the Iso Boot Image donwloaded at step 1.
6. Next, edit the “.vmx” file created by VMWare next to the VM: Add this line just after the first one: bios.bootOrder = “cdrom”
7. Now start the VM. It shows a menu with various entries named “Nanoboot-5.0-4528 xxx”. Pick the one to “Install/Upgrade”.
8. Run next the Synology Assistant. It will find a “DiskStation” not yet installed. Select that one and right-click to “Install” it.
9. When prompted for the Installation File, pick the pat file downloaded at step 2.
10. Proceed until the installation is completed (Give a name to you new Synology. No need however to setup a QuickConnect ID).
11. Enable the Backup https://www.synology.com/en-us/support/downloadService via the Start Menu > Backup & Replication > Backup Service > Enable Backup Network Service.

You are now ready to backup your actual Synology.

I did create a second Virtual Synology with the RAID 0 volume still available on the two old 2TB! Doing so, I will still be able to access all my data and settings if by any chance some have not been correctly restored.

1. Take the latest Boot Image iso available to start a “DSM” in a VMWare (Nanoboot-5.0.3.2 DSM 5.0-4528 x64) here.
2. Get the Synology Assistant from here and install it.
3. Use VMWare Workstation 10 to create a new VM (You may NOT create a Shared as those do not support physical disks. Also you better have to run VMWare as Administrator otherwise adding physical disks could be disabled):
   1. Create a “Custom (Advanced)” virtual machine
   2. Linux, version “Other Linux 2.6.x kernel 64-bit”
   3. With 1 processor, 2 cores
   4. 1024MB Memory
   5. Using a Bridged network
   6. LSI Logic Controller
   7. SCSI Disk Type
   8. And add the two old physical disks. Notice: the order is important. If they are not in the correct order, the DSM won’t start and report a disk access failure. No panic: simply swap the disks and retry 😉
4. Instead of starting the new machine immediately, edit the settings: the CD/DVD must be changed to use the Iso Boot Image donwloaded at step 1.
5. Next, edit the “.vmx” file created by VMWare next to the VM: Add this line just after the first one: bios.bootOrder = “cdrom”
6. Now start the VM. It shows a menu with various entries named “Nanoboot-5.0-4528 xxx”. Pick the one to “Install/Upgrade”.
7. Run next the Synology Assistant. It will find your old Synology “Migratable”. Select that one and right-click to “Migrate”. The RAID 0 Volume is detected automatically and the DSM should load. If it fails around 50%, swap the physical disks and restart the VM. They are probably not in inserted in the correct order (I did swap them physically in my PC – as using bays- but I could have removed them from the VM configuration and re-added them in the right order).
8. NB: installing with the option to download the latest DSM version failed. I had to download and use the pat file DSM 5.0-4528 available here.
9. Give this new Synology a unique name and disable any service that would conflict with one already running somewhere else.