Partitions of size > 2TB: How do we implement GPT, GUID, EFI and gdisk?

The question is not philosophical, but rather practical. We'll be moving to larger hdd's soon. For the entire Kirkwood community... ALARM folks please chime in to as we all use Linux and U-Boot..

What do we need, from the ground up? What is missing from this list?

• a kernel that has support for EFI & GPT
• gdisk utilities in A) our Wheezy Debootstrap script B) in any future Rescue System (in NAND)
• U-Boot that recognizes GUID/GPT/EFI
• changes to e2fsprogs (? : I'm not aware of any changes that need to be made for this, but just want to make sure...)
• ?? what else

Stuff to consider:
http://www.rodsbooks.com/gdisk/hybrid.html
http://www.rodsbooks.com/gdisk/index.html
http://forum.doozan.com/read.php?2,6309,6313#msg-6313

...more?... better?...

Or is this something that is not a priority here. Is it something that a trivial workaround can solve transparently and seamlessly?

=====================================================

• davy's Github Repo's rescue-dg

Edited 2 time(s). Last edit at 05/15/2012 05:08PM by davygravy.

The easiest method is GPT+Hybrid. Enabling GPT disk access is quite easy, and is supported by the ALARM kernel out of the box.

u-boot can read the hybrid to get to the boot partition, and then the kernel reads the GPT. The obvious flaw in this is the ordering of the partitions could be flawed by a user so that the boot/rootfs partition are in opposing orders (I won't go into detail, read up on hybrids) but so long as the are appropriately matched, you should be ok.

One possible option:
GPT: rootfs, boot, data
Hybrid MBR: boot, hidden

Thus to u-boot the boot partition shows as the first partition, and to the kernel, rootfs shows as the first partition, happily making /dev/sda1 accurate (or whatever parlance wished)

handy reference...
http://www.rodsbooks.com/gdisk/walkthrough.html

gdisk on the RescueV2.8 is now tested at least a little bit and works... I unfortunately don't have a 3TB drive to check it out on (in terms of > 2TB)...

and the final uboots work w/ EFI...

=====================================================

• davy's Github Repo's rescue-dg

Edited 1 time(s). Last edit at 05/26/2012 03:58PM by davygravy.