Installation on 4TB drive

I am having trouble installing RancherOS on a 4TB harddrive.

I get it booted off thumb drive, and it installs correctly with ros install, but it’s only using 2TB of the 4TB harddrive. I get this message in fdisk:

The size of this disk is 3.7 TiB (4000787030016 bytes).
DOS partition table format can not be used on drives
for volumes larger than 2199023255040 bytes for 512-byte sectors.
Use GUID partition table format (GPT).

I think I need to use GPT, rather than MBR. I can’t seem to convert it after installation, which insists on MBR re-partitioning. I thought about using another drive to be the “boot drive” and partitioning the large drive for after boot, but it’s a small computer with only room for 1 harddrive, and I’d prefer to not have a thumbdrive poking out, if at all possible.

I’d really like to use RancherOS, but I’m not sure how, in this scenerio.

If no one has any info on how to make ros install work with GPT, I bet I could cobble something together if I knew the files that need to be copied. Maybe I could manually partition, install grub, and copy the OS files? Where are those located?

ros install does a pretty standard manual install behind the scenes, so it’s definitely possible to do yourself. The installer script is located here and that should be a pretty helpful reference.

Thanks! This does seem pretty straightforward. Maybe I could improve it to handle cases like mine ( “custom partition-scheme” CLI flag?) I ended up just installing a light ubuntu server (with GPT + BTRFS) and getting docker + rancher working on it. I will do it all manually, following the script, when I get home. I’d be happy to document the process for the wiki, if there’s interest.

We’re planning on reworking a lot of the installer for v0.8.0, so some notes on what you end up doing would certainly be appreciated!

I can’t be sure, but I think the dd bs=440 count=1 if=/usr/lib/syslinux/mbr/mbr.bin of=${DEVICE} is the part that is forcing the MBR partition scheme? On these instructions I notice the bit about gptmbr.bin and wonder if it might make sense to simply detect the partition scheme before the dd call, or maybe adding a flag -g for “use GPT instead of MBR”. I’ll have to play with it when I get home. Is this a PR worth making, or is the rework going to be significantly larger that I shouldn’t bother?

Yes, its always worth making a PR!

Its very useful to know how other people use the tools we work on - otherwise we’re just writing code that we think will be useful!

I do expect to be re-writing the installer in go this week - but at the moment, I’m fighting with aws, osx and windows home edition.

here is the initial change, but I can’t test until I get home. What other scripts get run in ros install? I’d like to test all of them to make sure something else doesn’t clobber it.

@konsumer raised a PR : and I’ve made some additions to it, which once merged will get us part of the way there.