I booted up the device with all the HDDs removed (making sure I knew which one came out of which slot) and exported the configuration.
Looks like it is simply a gzip'ed text file which I unzipped using WinRAR and took a look at the text file. Albeit with what look to be a bunch of Linux format character returns which don't show up nicely in Wordpad (too lazy to copy the file to my Linux box). It I were coding it thats what I'd do for a backup export - simply gzip the text file before presenting to the user for saving.
It looks like the appropriate areas of the config file might be:
<dsk_mgr>
<hdd_config>
<raid_auto_sync>1</raid_auto_sync>
</hdd_config>
<dsk_diagnostic></dsk_diagnostic>
<volume_mapping>
<volume_1>Volume_1</volume_1>
<volume_2>Volume_2</volume_2>
</volume_mapping>
<smart>
<test>
<hd_a>Pass [2014/04/27 08:23:48]</hd_a>
<hd_b>Fail [2014/05/01 17:52:35]</hd_b>
<hd_c>Pass [2014/05/01 17:53:21]</hd_c>
<hd_d>Pass [2014/04/27 08:17:43]</hd_d>
</test>
<hd_a_sn>WD-WMC1H0096199</hd_a_sn>
<hd_b_sn>W240B882</hd_b_sn>
<hd_c_sn>W2F08WWM</hd_c_sn>
<hd_d_sn>WD-WMC1H0065319</hd_d_sn>
</smart>
</dsk_mgr>
I'm gonna put the drives back in to the unit now and see if booting it up with no HDDs has caused it to rethink its opinion of the RAID status and try and detect the config off the drive signatures. Might be a long shot but I think it's worth it.
Next step after that is removing all 4 Production drives and replacing with 2 drives I've got lying around, configure them in a RAID1 set, export the config and hope I can reconstruct the RAID and Volumes portion of it from the config backup (substituting RAID5 and more disks as appropriate). I'll make sure I use Linux to edit the file
I'm also gonna have a look around and see if there is a guide to the options in the config file. Perhaps someone has cracked it open before, made changes and documented it. Or DLink provide a guide (unlikely).
Still..... sing out if anyone can help with a pre-existing config either full or just the relevant portions.
Cheers,