I have an Inspiron N5110 laptop, and I am wondering if it is possible to install a SSD as a boot drive, and leave the stock HDD in as a storage drive. I have seen people that install a SSD caddy in place of their optical drive, and I am wondering If this is possible, and what caddy I would need. If it is not, I would be happy to hear any other suggestions!
It's not possible - the system takes only one 2.5" drive. You must replace the hard drive with the SSD.
There are adapters that will let you mount the original hard drive in place of the DVD drive - but you can't use the drive there as a boot device.
Be sure you have collected everything you need before starting the replacement process -- replacing a hard drive in this model is far from trivial. The mainboard needs to come out, since the drive is mounted on the underside of it. See video link below.
N5110 hard drive replacement
I've seen threads on this forum about the same topic, and Dell employees have said that this works. I'm not doubting you, I would just like clarification. Why would the computer not take more than one drive? It already has 2 SATA devices plugged in, the hard drive and the optical drive. Why would the system not accept a piece of hardware running the same interface, just with a different purpose? To repeat, I'm just looking for an explanation here, I don't doubt what you have said.