Two Start-Up partitions on one SSD

zuul-studios · Post by **zuul-studios** » Wed Oct 14, 2015 5:37 am

Hello -

Are there any problems or negative issues that might exist if I put two Start-Up partitions on one of my internal SSDs in my MacPro (noted in my signature)? Currently, I have configured two separate SSDs that are used as Start-Up disks. Both house OS X 10.10.5, but one is used for my modest audio/video projects and the other for more everyday use. I simply wish to consolidate and have the two Start-Up disks on one SSD.

Thank you for any insight to this.

MIDI Life Crisis · Post by **MIDI Life Crisis** » Wed Oct 14, 2015 7:15 am

The only problems I see are updating notifications, alerts, mail, etc. I suppose I should just shut that down in the alternate startup partition but don't use it enough to bother. But other than that, there shouldn't be an issue.

HCMarkus · Post by **HCMarkus** » Wed Oct 14, 2015 7:32 am

As long as you have adequate space, works fine. Make sure trim is enabled on both partitions.

MIDI Life Crisis · Post by **MIDI Life Crisis** » Wed Oct 14, 2015 9:34 am

HCMarkus wrote:As long as you have adequate space, works fine. Make sure trim is enabled on both partitions.

On my 2013 Mac Pro trashcan Trim is NOT recommended or needed as it is built into the OS (or something like that). Just sayin'...

mikehalloran · Post by **mikehalloran** » Wed Oct 14, 2015 9:53 am

MIDI Life Crisis wrote:
HCMarkus wrote:As long as you have adequate space, works fine. Make sure trim is enabled on both partitions.
On my 2013 Mac Pro trashcan Trim is NOT recommended or needed as it is built into the OS (or something like that). Just sayin'...

True. TRIM is part of the OS and enabled on Apple SSDs by default.

For third party SSDs, you boot from the drive, then enable it by running the following in Terminal:

sudo trimforce enable

You may need to do this from each partition. I could be wrong but it's easy enough to check. Go to About This Mac, find your drive and look for TRIM Support: Yes Now drill down into each partition and see if it reads the same.

This works in OS 10.10.4 and later. Interestingly, it also works if run on a boot drive connected via USB or Thunderbolt. I was surprised to see that last month since it is not mentioned anywhere. I prepared new SSDs for a number of iMacs via USB before I installed them.

zuul-studios · Post by **zuul-studios** » Wed Oct 14, 2015 10:55 am

Thank you, kindly, for the thoughtful comments. Your time and your expertise are sincerely appreciated and respected. I'll be putting the two Start-Up Partitions on the one new SSD that I recently purchased (and use the older two SSDs for video editing).

(I have TRIM enabled on all of the internal SSDs.)

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