Revitalize 2011 HDD by formatting?

[JocoFoto]

The 2TB HDD in my 2011 iMac has been spinning for 5 years now and I am very aware that the chances of failure are increasing.

Since some months I am booting from an external SSD via Thunderbolt which works great. The HDD was 99% filled with pictures in Aperture libraries (which were back up-ed on external drives)- and given my concerns on the longevity of both Aperture and the HDD, I decided to reorganize and move everything to an external disk. The internal HDD is now intended for files of current projects, to be moved when finished.

Going forward I have 2 question:

1) how can I remove OS-X and anything related to that from the internal HDD? Mac OS updates sometimes get confused by the 2 volumes and whilst updating the SSD, the iMac boots on the HDD (despite the boot disk setting). So I prefer to get rid of anything like that.

2) I was told low level formatting of a disk would re-vitalize it i.e. restore the magnetic capability. Which again I am told would make the disk faster to read but also reduce the risk of read-errors piling.

Again I am being told, so would love to hear your opinion on this. I can also imagine putting an aging disk through a lot of cycles necessary to deep-format, mechanical failure is a risk.

 

[Fishrrman]

OP:

First, moving to an SSD "external booter" was a GOOD idea.
I boot and run my 2012 Mac Mini that way -- runs great.

Next:
You DON'T need to do a "low level" format.
All you need to "revive" the internal HDD is to:
1. Back it up to another drive
2. Re-initialize it using Disk Utility
3. Restore it from your backup (you may want to be "selective" about what you restore).

WHY do it this way?
Because (when you "copy back over"), the re-copied files will be written "contiguously" to the drive, eliminating the thousands (millions?) of "bits of free space" that have fragmented the drive over time. It should also group whatever free space is left "at the end" (i.e., "behind" the data files).

One other thought:
I have my own internal HDD (in the Mini) partitioned.
I use the first partition for a cloned backup of my boot SSD. This means I can boot from it in an emergency. A Mac user should always, ALWAYS have a second fully-bootable drive or volume close-at-hand. Always. MacRumors.com is filled with forum posts from folks who are suffering the "I can't boot!" syndrome. Keep that second fully-bootable volume around and you will NEVER have this problem.

I use subsequent partitions (on the internal HDD) for my files (important data files, music, media, etc.).