Related keywords: discard, thin provisioning.

Links

File systems/storages supporting sparse

Pretty much all filesystems: BTRFS, NILFS, ZFS, NTFS, ext2, ext3, ext4, XFS, JFS, ReiserFS, Reiser4, UFS, Rock Ridge, UDF, ReFS, APFS, F2FS

NFS: since 4.2, make sure to mount as vers=4.2

qcow2

Compare:

ls -lh myfile
du -sh myfile

Or

dd seek=10G if=/dev/zero of=sparsetest bs=1 count=1 status=none
du --block-size=1 sparsetest

8192 sparsetest

du --block-size=1 --apparent sparsetest

10737418241 sparsetest

If these outputs are very different, sparse is supported :)

rsync -S