Netboot - Cant Unmount disk

[jwojda]

Since Lion (now on ML 10.8.2) when I try to do a diskutil eraseVolume on the local disk, i can wipe the recovery partition, but when I go to do the main drive it returns can't unount disk. From there I reboot the system and try the main partition again, and AGAIN it returns can't unmount. When I reboot a 3rd time, then it allows me to wipe the partition.

I've tried running the mount command but it returns something along the lines of can't mount the disk.

Is there something wrong in my NBI's that I've bene making for 10.7 and now 10.8?

[jarednichols]

Sounds like you're not in diskless mode.

[Kumarasinghe]

Try this method described in the link below;

http://www.macos.utah.edu/documentation/administration/setup_netboot_service_on_mac_os_x_10.6.x_clie...

[jwojda]

Sorry, was dealing with a down server today. We do have diskless booting enabled. It's a pretty odd occurrence, some machines do it, others do not.

Usually on the 3rd reboot the unmount / remount works fine and the images proceed as expected.

I've also tried just typing mount and that doesn't seem to do the trick either.

[tkimpton]

Be careful with modifying to get shadow files to write to ram. I screwed up my server doing that. Luckily I used SuperDuper to Clone the entire server before hand.

[fritz_schlapbac]

I had a similar problem with 10.8 and 10.7 NetBoot images. The workaround with the RAM shadow file worked sometimes and sometimes not.

Finally it turned out that the problem was a Thunderbolt Ethernet Adapter. I have one Thunderbolt Ethernet Adapter which doesn't work for diskless NetBoot. When I use this adapter the local harddisk has /private/var/netboot as mount point and it's not possible to unmount the harddisk for imaging.

With other Thunderbolt Ethernet Adapters and the USB Ethernet Adapters the problem doesn't exist. I can reproduce this 100% with different laptops (MacBook Air 2011 and 2012, MacBook Pro Retina).

I have no idea why an adapter could cause this problem. And it took me several hours of searching because I searched completely in the wrong places to find a solution.

[jwojda]

fritz.schlapbach - i've had this problem on MBAir's with the usb and the TB dongle, and I've had both work with the TB /USB dongle. I went back into the NETBOOTSP0 folder and saw the share of AFP wasn't enabled.. sO I reenabled it and haven't heard back from the tech - but that could be because they haven't tried since then...