I thought I should provide the conclusion of the Terastation story. I did finally receive and install the new WD 500GB hard disk, but sadly the RAID rebuild did not preserve my data. I am still wondering if there was something I could have done differently to preserve the redundant data – if I had put the brand-new drive in upon the first reported error, would the array have rebuilt without any problems? I may never know.
Regardless, I had to delete and recreate the RAID array from scratch – it only took about 12 hours to build and format for 750GB. So, then I began the process of copying the data back from the external USB disk which I use as a nightly backup of the Terastation. In the end, everything was copied back where it should be and the PCs and Sonos players in the house are all mapped back to the Terastation shares. I did put a new 500GB external USB disk in place for the nightly backups, and I rotated the former disk off to my storage unit for safe keeping.
What’s next? I think upgrading my Ubuntu NAS to Natty Narwhal (v 11.04) which is planned for April 28, 2011.