BIOS booting from disks > 2TB

José María Alcaide jose at
Wed Nov 19 09:32:25 UTC 2014

On Nov 19, 2014, at 8:06 AM, Pokala, Ravi wrote:

> When you perform your installation, just make sure to select the GPT
> option for partitioning. The installer (either `bsdinstall' (for stock
> FreeBSD), or `pc-sysinstall' (for PC-BSD / FreeNAS)) should create both
> primary (near start-of-disk) and backup (at end-of-disk) GPT tables, and
> install the appropriate bootstrap code in the proper locations.

Yes, bsdinstall flawlessly creates both primary and backup GPT tables even using disks > 2 TB, by virtue of the FreeBSD kernel. The problem arises at the first stages of booting, when gptboot tries to compare the primary and backup tables *using the BIOS disk services*, which are not able to reach anything after the 2 TB limit. As a consequence gptboot fails, stating that it did not find the GPT backup table.

Jose M. Alcaide

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