ReadayNAS Ultra 4 data recovery after dying

Do you have a saved copy of a log file?  That will tell you which you were using.

The recovery methods are quite different because of the different volume structures used (LVM/MDADM and GPT for 4.2 and MDADM and BTRFS on OS6).

The easiest recovery method, assuming the volume was not damaged when the unit "blew up" (which will affect any recovery method) is to put the drives in a replacement ReadyNAS.  But you'll also need to know which OS you were running to do that.  And, of course, you'd be buying used equipment, which always carries some risk.  And there is the question as to whether you want to continue using a NAS from a company that has basically abandoned it.

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laurensat101 wrote:

I'm afraid I can't recall, it's been a while since I had updated it, that's for sure.

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OS-6 would have required you to back up all the data and use a special conversion procedure.  Then rebuild the NAS and restore all the files from backup.  OS-6 has a very different look from the older Frontview. Likely something you would remember doing.  

In addition to Sandshark's suggestion, you could use RAID recovery software in a Windows PC. As you posted, you'd need to get suitable USB enclosures, and also enough storage to offload the data.

ReclaiMe will recover the files for either OS-6 or OS-4.  R-Linux for Windows will recover OS-4, and is significantly cheaper.  But you can download both first (before purchase) and see if either can recover your files. 

Also - if you can connect even one disk to a Windows PC, then you can check them (one at a time) with vendor tools.  Windows won't mount them, but the vendor tools will find them.  Then you'd have some confirmation that the disks are still ok.  Always a good idea to label the disks by slot as you remove them.