I've just set up a NAS with mirrored drives. One precaution I took was to buy the disks from 2 different suppliers, so if I would get disks from 2 different batches. The idea is that if the disks in a particular batch tend to fail at the same age, having disks from different batches reduces the risk of near simultaneous failures.
Bloody he'll that's a worry! I use a mirrored nas as my backup solution too and I really wouldn't expect the second disk to fail so quickly. Is the NAS quite old? 3 drives out of 6 in a couple of days does suggest something going on. At work we have disk arrays with a couple hundred disks in and get maybe 1 disk every couple of weeks failing. I suppose it could just be bad luck....
In terms of te holy grail of reliable backups going onward I guess we all need to fork out for more expensive NAS with more disks and use RAID 6 where loss of 2 disks can be tolerated. Soon we will all have storage arrays at home I suppose which does seem a bit OTT. I know some people pay a monthly fee to back up online which is another option. The only thing I really care about losing is the photos of the kids so I periodically copy them from the nas to my old hard drive and store it out of the house but that's a bit hit and miss.
If the only problem with the backup is broken pins on a cable or connector, then the data is intact and a suitably competent person can retrieve it all. It's possible a competent local computer shop might be able to sort it for you reasonably cheaply.
If not, then somebody like OnTrack Data Recovery should be able to get all the data off. I've never had to use a data recovery firm, so I don't know what it should cost.
Sounds like a lot of bad luck for them all to fail at the same time. Any cause for the failure identified? Power surge - I have lost a drive due to that, it actually killed the laptop completely but removing the drive it spun for a minute, then it died as well.
It does make you wonder what backup media should be used these days.
Me and DH have a computer each, two hard drives each, and we have a NAS server with two 1.5TB hard drives in it. Day before yesterday one of the 1.5TB drives failed, we thought we were ok as the second 1.5TB drive was the back up. Except then that failed. We managed to retrieve some data and filled up both my hard drives, then went to put the rest on to one of DH's hard drives, except then that failed too.
DH managed to revive the backup 1.5TB, except then the pins for the SATA cable snapped.
So now we are down 3 hard drives, lost half our data and no space to back up what we did save.
You'd think that with 6 hard drives we'd actually stand a chance of not losing so much data!