Hello. We do not advise on data recovery procedures as there are third party companies who can provide the service. Back to your questions. There is no option to install your new HDD  on the T620 without loss of data even outside of RAID 5 array. Yes, the cheapest option for you is to use an external adapter in which the new HDD will be recognized as another drive. However, there could be a possibility of corruption of your data. It is fine to re-install your SSD back into the empty slot and automatically be recognized as part of the array.
Hello Everyone, I kept telling my wife to drag all her files into Google Drive and needles to say, she never did. BAM! Her laptop suddenly died and now she has no access to her files. I was going to order a 2.5" external hard drive adapter, but then I thought of trying something else first.   I have a PowerEdge T620 with two SSD's for the OS and 4 in RAID for the data. I believe the two SSD's are in RAID 1 and the other four are in RAID 5. However, I am not sure if this is even important... Having said this, here is/was my plan. I took one SSD out and used that enclosure to install her laptops HDD. I then inserted the "new" drive to an open bay. MY PowerEdge has a total of 12 and I used number 7?! I would think. Anyhow, it wasn't the one where the SSD was in and none of the other 4. I left all that alone. I then restarted the computer thinking that the "new" drive would just show up under "my computer", but of course it didn't. I am pretty sure I have to go and enable it, since it is not "part" of the RAID array. I mean, not really, but somewhat. If you know what I mean?! My question now is, can I somewhere "enable" the new HDD without making it part of the RAID 5 array? If so, how?  Thanks, G  p.s. it is probably cheaper to just go and buy an external adapter, right? LOL.  p.p.s. What happens again if I plug the second SSD back into its bay? Will the computer automatically recognize it? I think now as I did this once before? Don't remember though.
Do I have to add a HDD to RAID?