Setting up dual hard drives

[JustTryin]

I have a 2011 21.5" iMac and I'm looking to replace the 500Gb HDD with a 500Gb SDD. I have a million different guides telling me how to do this so that's fine. What I also want to do is use my old HDD as a secondary drive for storage to keep the main drive as free as possible, by replacing the optical drive (which I will replace with an external USB DVD drive). I have also seen guides explaining how to do this.

What I am unsure about, and would like to resolve before I go and buy all the stuff I need and start taking things apart, are the following issues:

1. When I boot up after installing the new SDD and swapping the HDD over, if I set up a brand new install of OSX on the SSD, will the mac automatically see this as the main drive and ignore any OSX on the secondary HDD on subsequent restarts?
2. Assuming the HDD is seen as a secondary drive, and I haven't formatted it after removing as main drive, will I be able to access all my original files from it as a secondary drive or would I need to back up everything using, time machine for example, and restore files I need from there.

Thanks.

P.S. In case I have missed answers to these elsewhere, I apologise, but I did search for quite a while before posting this.

 

[Brian Y]

To answer your question - installing OS X will set the startup disk to the volume you installed to. If for some reason it doesn't, hold ALT while powering on and you can choose your new install. Then under System Preferences -> Startup Drive you can choose (bless) the drive you want to boot from.

You can access everything on your old drive no problem .

Do you use your CD drive? If not, and you don't mind buying a few additional cables/doing a bit of tinkering, you can go one better. You'll need:

- A cable for the ODD SATA port for a SATA HDD
- A regular SATA cable
- A SATA power splitter

On those iMacs, the HDD and SSD SATA ports are 6Gbps, the ODD SATA port is 3Gbps. Using the above you can move the regular HDD to the ODD SATA port (3Gbps is enough for the stock HDD), and add 2 SSDs - to the HDD and SSD SATA ports. You can then set these 2 SSDs up in software raid 0, which gives you close to 1GB/s transfer speeds.

It's a pretty stable config, my due-to-be-retired 2011 27" has been running it for a few years, and a few others here have done it. It might be pretty cramped fitting it all into a 21 though, but as upgrades go, it's the best thing you can do to them. Be prepared for some sweary cabling (but you're going to have that anyway as the SATA ports are all on the back of the logic board - so it's either logic board out, or if you've opened them a few times, you can do it by careful lifting of the board with the RAM removed - but that's not something I'd suggest a novice to do).

 

[JustTryin]

Thanks for the info. Very helpful. But just to clarify something...

You talk of a 6Gbps HDD SATA port (which I assume is what my current HDD is connected to) and a 3Gbps ODD port, which my CD drive is connected to, but also an SSD drive. Is this something that is unused at present?

If this is the case, then aside from the option of setting up twin SSDs in a raid 0 configuration (which I'm not discounting), couldn't I just add the SSD and keep the HDD where it is, rather than replace the ODD with the SSD?

 

[Brian Y]

Thanks for the info. Very helpful. But just to clarify something...

You talk of a 6Gbps HDD SATA port (which I assume is what my current HDD is connected to) and a 3Gbps ODD port, which my CD drive is connected to, but also an SSD drive. Is this something that is unused at present?

If this is the case, then aside from the option of setting up twin SSDs in a raid 0 configuration (which I'm not discounting), couldn't I just add the SSD and keep the HDD where it is, rather than replace the ODD with the SSD?

Yep, you could.

The 2011 iMacs were configurable with a HDD and SSD together, so there’s a third SAT port lurking back there. This is why there’s a gap under the cd drive.

You’ll need a power splitter though, but it’s a regular SATA connection