On Tue, 26 Apr 2016, Elliott, Robert (Persistent Memory) wrote:
The UEFI specification is not ambiguous - you should always look for the backup GPT Header at the last LBA: "Two GPT Header structures are stored on the device: the primary and the backup. The primary GPT Header must be located in LBA 1 (i.e., the second logical block), and the backup GPT Header must be located in the last LBA of the device." If the primary GPT Header is corrupted (e.g., CRC is bad), you cannot trust any fields in it, including the Alternate LBA field.
I'm well aware of this, and is really what I meant with 'ambiguous' (which was ambiguous in itself). All I'm arguing is that I don't see a solid reason to change the default, when we have (and have had for a long time) the gpt param alternative.
The Alternate LBA field is there to help you tolerate failures while growing or shrinking the block device size (not important for individual physical drives, but an issue for logical drives presented by RAID controllers).
I have nothing against the agpt, just pass a boot param and voila, you can use it. This is not some sort of recent regression we are talking about here. How is this such a burden all of a sudden? Thanks, Davidlohr -- To unsubscribe from this list: send the line "unsubscribe linux-efi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
