Thank you for purchasing through links and ads on this site.
diglloyd Deal Finder...
Buy other stuff at
Upgrade the memory of your 2018 Mac mini up to 64GB
Handpicked deals...
$2998 $2498
SAVE $500

$350 $280
SAVE $70

$1598 $998
SAVE $600

$399 $329
SAVE $70

$1069 $869
SAVE $200

$1299 $899
SAVE $400

$1499 $999
SAVE $500

$1499 $1019
SAVE $480

$1799 $1349
SAVE $450

$3698 $2998
SAVE $700

$2397 $1897
SAVE $500

$1199 $898
SAVE $301

$1299 $1169
SAVE $130

$4499 $3999
SAVE $500

$1399 $1099
SAVE $300

$1499 $1299
SAVE $200

$4499 $3149
SAVE $1350

$2299 $1599
SAVE $700

$1799 $1349
SAVE $450

$2998 $2498
SAVE $500

$2199 $1999
SAVE $200

$430 $230
SAVE $200

$3399 $2199
SAVE $1200

$6299 $3599
SAVE $2700

$400 $280
SAVE $120

$1499 $1019
SAVE $480

$1279 $719
SAVE $560

$1699 $1549
SAVE $150

Suggested Boot/Master Volume Partitioning for Large SSD

Last updated 2014-12-12 - Send Feedback
Related: Mac Pro, Other World Computing, SSD, storage

OWC Mercury Aura SSD for Mac Pro: 1TB about $899, 2TB about $1479.

Please see Terminology: Volume vs Drive.

How to use all that fast SSD space?

With a 2TB SSD (or 1TB), it can be useful to separate the startup volume (Boot) from the main bulk of user generated data (Master, as in “master copies”).

If something goes wonky with the boot volume, it’s possible to install over it, or even to erase it without affecting the Master volume. Moreover, it’s a useful organization approach. See Separate Data from System and Applications.

As shown, a 2TB OWC Mercury Aura SSD for 2013 Mac Pro has been partitioned into a 200GB Boot volume and a 1720GB Master volume using Apple’s Disk Utility. [Disk Utility description as “External” is erroneous, as is the drive name of Accelsior].

Continues below.


With SSDs smaller than 1TB, partitioning this way balkanizes the space (wasting it), and is thus not recommended.

Unlike a hard drive, partitioning an SDD does not affect performance; it is organizational/structural only.

However, it is wise to choose appropriate capacity partitions so as to not waste capacity on one or the other. Since most user data will go on Master, the Boot drive can be relatively small—MPG uses 120GB as a boot volume.

To partition the internal SSD, boot off any external volume, e.g.:

  1. Clone the internal startup volume to any external volume; reboot off the external volume (set the startup volume).
  2. Partition the internal SSD as desired.
  3. Clone from the external boot volume to the internal boot volume.
  4. Set the startup volume to the internal boot volume, reboot.

Upgrade Your Mac Memory
At much lower cost than Apple, with more options.
Lloyd recommends 64GB for iMac or Mac Pro for photography/videography.

Organization and backup

The system software and applications should all go onto Boot. Defaults for Mail, Calendar and similar should in most cases remain on Boot (in the user’s home folder).

User-generated data such as word processing, spreadsheets, Lightroom Catalogs, etc should go onto Master. Large files (videos, raw image files, etc) do not benefit from an SSD and are best dealt with by using an external volume, the OWC Thunderbay 4 being an excellent choice for those needing high capacity.


Backup both Boot and Master, because various important things will still be on Boot. Plus it is very useful to have a bootable clone.

Backup is straightforward with cloning; see Using Cloning as a Backup Strategy:

  • Clone Boot to BootClone
  • Clone Master to MasterClone

Save the tax, we pay you back, instantly!
View all handpicked deals...

Beats by Dr. Dre Studio3 Wireless Bluetooth Headphones (76ers Blue / NBA Collection)
$350 $280
SAVE $70 | Terms of Use | PRIVACY POLICY
Contact | About Lloyd Chambers | Consulting | Photo Tours
Mailing Lists | RSS Feeds | Twitter
Copyright © 2019 diglloyd Inc, all rights reserved.
Display info: __RETINA_INFO_STATUS__