I was playing around with CoreOS in the last few days and i had a problem that the "installer" only created a 3GB GPT-label, with the problem that the backup header wasn't at the end of my disk but at the end of this 3GB section, so I couldn't just resize my rootfs to the full disk.
To resize the ROOT-filesystem we'll have to move this backup data to the end of the disk:
localhost core # gdisk /dev/sda
GPT fdisk (gdisk) version 0.8.6
Partition table scan:
MBR: protective
BSD: not present
APM: not present
GPT: present
Found valid GPT with protective MBR; using GPT.
Command (? for help): x
Expert command (? for help): e
Relocating backup data structures to the end of the disk
Expert command (? for help): m
Command (? for help): w
Final checks complete. About to write GPT data. THIS WILL OVERWRITE EXISTING
PARTITIONS!!
Do you want to proceed? (Y/N): Y
OK; writing new GUID partition table (GPT) to /dev/sda.
Warning: The kernel is still using the old partition table.
The new table will be used at the next reboot.
The operation has completed successfully.
localhost core # reboot
After a reboot we open gdisk again, delete the ROOT-partition and recreate it with the same starting sector and the default end sector (which normally is the highest possible value).
Partition type should be FFFF.
localhost core # gdisk /dev/sda
GPT fdisk (gdisk) version 0.8.6
Partition table scan:
MBR: protective
BSD: not present
APM: not present
GPT: present
Found valid GPT with protective MBR; using GPT.
Command (? for help): p
Disk /dev/sda: 234441648 sectors, 111.8 GiB
Logical sector size: 512 bytes
Disk identifier (GUID): 83A877DF-4A87-1E4A-B413-BEABFD879D68
Partition table holds up to 128 entries
First usable sector is 34, last usable sector is 234441614
Partitions will be aligned on 2048-sector boundaries
Total free space is 228543341 sectors (109.0 GiB)
Number Start (sector) End (sector) Size Code Name
1 2048 264191 128.0 MiB EF00 EFI-SYSTEM
2 2361344 2492415 64.0 MiB FFFF BOOT-B
3 264192 2361343 1024.0 MiB FFFF USR-A
4 2492416 4589567 1024.0 MiB FFFF USR-B
6 4589568 4851711 128.0 MiB 8300 OEM
9 4851712 5900287 512.0 MiB FFFF ROOT
Command (? for help): d
Partition number (1-9): 9
Command (? for help): n
Partition number (5-128, default 5): 9
First sector (34-234441614, default = 4851712) or {+-}size{KMGTP}: 4851712
Last sector (4851712-234441614, default = 234441614) or {+-}size{KMGTP}:
Current type is 'Linux filesystem'
Hex code or GUID (L to show codes, Enter = 8300): FFFF
Exact type match not found for type code FFFF; assigning type code for
'Linux filesystem'
Changed type of partition to 'Linux filesystem'
Command (? for help): w
Final checks complete. About to write GPT data. THIS WILL OVERWRITE EXISTING
PARTITIONS!!
Do you want to proceed? (Y/N): Y
OK; writing new GUID partition table (GPT) to /dev/sda.
Warning: The kernel is still using the old partition table.
The new table will be used at the next reboot.
The operation has completed successfully.
localhost core # reboot
After another reboot we now can resize the btrfs filesystem to the whole partition:
localhost core # btrfs filesystem resize max /
Resize '/' of 'max'
Using df -h / should now show the new size:
localhost core # df -h /
Filesystem Size Used Avail Use% Mounted on
/dev/sda9 110G 537M 109G 1% /
