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The subject line says it all, unfortunately. I just received a new iMac with a Fusion drive split by a 1.0TB SATA drive and 24.0GB SSD. I followed the instructions on this post as I've done in the past but couldn't seem to get it to work. I believe the issue here is with the size of the SSD being only 24GB.



3. Recreate the Fusion drive volume

To do so, execute the following command diskutil cs createVolume <Logical Volume Group ID> JHFS+ "Macintosh HD" <Capacity of the Fusion drive>. Capacity must be in XXX.Xg for volumes less than 999.99GB in size, or X.Xt for volumes 1.0TB or greater


The combined volume size for my iMac is 1.024TB but as the above section details, I must follow the X.Xt format which would force me to specify 1.0t. I've not only tried formatting the drive as 1.0t and 1.1t but regardless of which size is specified, a NetBoot to my AutoCasperNBI does not successfully launch. No other clients in the network are having this issue and the network connection is sound. Does anyone have any experience with this in their environment?



Alternatively, I could just leave it as is (see picture below of storage drives) and just automatically hide the "Fusion HD" drive. I would need to have this hidden on every session. For example if a new user logs onto the machine, this needs to remain hidden--the same goes for any system reboots. I also cannot simply hide all drives as I'd like to have the "Macintosh HD" shown on the desktop and in the Finder windows. Does anyone have a solution for this approach?

Specifying a size of zero "0" defaults to using all available space...
This is the fusion drive part of my larger reformat script that wipes both volumes and creates a new fusion with them, maybe it helps.



diskutil partitionDisk $The_HDD 1 GPTFormat jhfs+ "HDD Fusion" 0

diskutil partitionDisk $The_SSD 1 GPTFormat jhfs+ "SSD Fusion" 0

sleep 2

diskutil cs create fusion $The_SSD $The_HDD

sleep 2

CS_Group=$(diskutil cs list | awk '/-- Logical Volume Group / {print $NF}')

sleep 2

diskutil cs createVolume $CS_Group jhfs+ "Macintosh HD" 0

Hey there, @Look! Thanks for providing some feedback, it was very helpful. I performed what you suggested but first added a few lines to wipe the existing volume. These were all performed in Terminal from Recovery Mode.



diskutil cs list
diskutil cs delete <Logical Volume ID here>
diskutil partitionDisk $The_HDD 1 GPTFormat jhfs+ "HDD Fusion" 0
diskutil partitionDisk $The_SSD 1 GPTFormat jhfs+ "SSD Fusion" 0
sleep 2
diskutil cs create FusionDrive $The_SSD $The_HDD
sleep 2
CS_Group=$(diskutil cs list | awk '/-- Logical Volume Group / {print $NF}')
sleep 2
diskutil cs createVolume $CS_Group jhfs+ "Macintosh HD" 0


After performing the above commands, I was left with a properly formatted Fusion Drive but was still unable to launch my Casper NetBoot. I was able to see our in-house Casper NBI from the available disks in the Startup Manager (image below of Startup Manager is for reference and provided as a stock image from Apple). After selecting it, I was taken to a black screen with the prohibitory icon. Any thoughts as to why I am unable to successfully boot into my Casper NBI? Please note that imaging from our Casper NBI works perfectly in all other cases and from the same port, with the same Ethernet Cat6 cable.




Most common source of not-bootable NBI: What OS X version (build) is your Casper NBI?
The new iMac 2015 require 15A2301 or 15A4310 (i.e. a special build version of 10.11.0)
A NBI based on generic 10.11.2 will work too.



edit: the 2015 iMac models are not yet included in kbase HT204319

@mjsanders Godammit, I feared that might be the case. Our NBI is on 10.10.5 :|

AutoDMG (v1.5.4) + AutoCasperNBI (v1.3.3) are a man's best friend. Creating a 10.11.2 NBI from my machine running 10.11.2. I'll follow up once I'm able to test this but think that this'll resolve my issue in conjunction with the above drive re-configuration in Terminal from Recovery Mode.

@mjsanders @Look @bentoms @Behlmer Hey there, gents!



I've updated my imaging server to 10.11.2 and on there used AutoDMG (v1.5.4) to create a DMG image which I then used with AutoCasperNBI (v1.3.3) to produce a working NBI. I verified that this now shows up in my Server app on the imaging server and that I am able to see and select this on machines that I'd like to image. However when running the NBI, the machine attempts to load the installer and then reboots to the Macintosh HD eventually loading the login screen.



I have selected default settings with the exception of a custom desktop wallpaper, specified the correct timezone and select the correct DMG and Casper Imaging 9.81 app on the imaging server being used. Any ideas as to why I am not able to successfully boot into the created NBI?

OK, you solved the version issue.
Now there is something else, try other things like:
-can other (older Mac's) netboot? (be sure no version issue)
-can you netboot at all at this subnet? (network admins do allow DHCP/bsdb/nfs/.. etc)
-etc..

@mjsanders I was able to find some documentation from a previous 10.10.5 NBI build in our environment and noticed that we had been specifying our internal AD's IP address for the Time Server. After adjusting that and creating a new NBI, we're back in business! Thanks, all :)

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