The cloud disk grew, the filesystem did not

The console moved a disk from 40G to 100G. lsblk shows the larger device; df -h still says 40G.

The resize changed the block device only. The partition table and filesystem are unchanged:

growpart /dev/vda 1
resize2fs /dev/vda1        # ext4
# xfs_growfs /             # xfs

growpart comes from cloud-utils-growpart and is preinstalled on most images. On GPT with no free space after the last partition it fails; sgdisk -e first moves the backup header to the end of the disk.

XFS grows but never shrinks, and ext4 shrinking requires an unmount. Snapshot before touching a partition table in production.