blob: b831666d0d24841600e360ef8d56e40b82b1b730 [file] [log] [blame]
{
"parent": "legacy_disk_layout.json",
"layouts": {
# The following number for size (4966) is determined such that the
# size of image with "base" disk layout is exactly 10GiB. GCE images
# are expected to be multiple of 1GiB. We choose 10GiB because it's
# the default boot disk size on GCE.
#
# For now, we determine the starting sector number of the stateful
# partition with cgpt (see below) on a built image. But ideally
# we should arrive at this number based on legacy_disk_layout.json.
#
# Partitions are expected to be aligned to 4096 block boundary,
# that is, 2 MiB.
#
# Starting with crrev.com/c/528047, 1GiB will always be added
# to the stateful partition size. Therefore, we leave room
# for it in the computation below to prevent the image size
# growing beyond 10GiB.
#
# number of 512-byte sectors in 10GiB: 20,971,520
# stateful partition starting sector: 8,704,000 (cgpt show /dev/sda)
# stateful partition size in MiB: 5,990 (2MiB aligned)
# stateful partition size less 1GiB in MiB: 4,966 (crrev.com/c/528047)
"common": [
{
# Kernel for Slot A.
"num": 2,
"label": "KERN-A",
"type": "kernel",
"size": "128 MiB"
},
{
# Kernel for Slot B.
"num": 4,
"label": "KERN-B",
"type": "kernel",
"size": "128 MiB"
},
{
# Board specific files, stores persistent configuration.
"num": 8,
"label": "OEM",
"type": "data",
"fs_format": "ext4",
"size": "32 MiB",
"uuid": "random"
},
{
# Used for Legacy Bios, and EFI Bios, not ChromeOS hardware
"num": 12,
"label": "EFI-SYSTEM",
"type": "efi",
"fs_format": "vfat",
"size": "128 MiB",
"uuid": "clear"
},
{
"num": 5,
"label": "ROOT-B",
"type": "rootfs",
"fs_size":"2 GiB",
"size": "2124 MiB",
"fs_format": "squashfs",
"fs_options": {
"squashfs": "-comp gzip"
}
},
{
"num": 3,
"label": "ROOT-A",
"type": "rootfs",
"fs_size":"2 GiB",
"size": "2124 MiB",
"fs_format": "squashfs",
"fs_options": {
"squashfs": "-comp gzip"
}
},
{
# STATE
"num": 1,
"size": "4 GiB",
"fs_options": {
# A consequence of this option is that some file system
# structures are initialized lazily when resizing,
# resulting in much faster resize2fs invocations.
"ext4": "-O metadata_csum"
}
}
]
}
}