Compare overlay2, aufs and devicemapper storage driver overhead for your workload.
Docker storage drivers (overlay2, aufs, devicemapper) manage how image layers are stored and shared. overlay2 has minimal overhead (~2%), aufs slightly more (~5%), and devicemapper uses block-level copy-on-write with higher metadata overhead (~12%). Total disk = image × (1 + overhead) + containers × writable_layer.
Total Disk
totalDisk = image × (1 + overheadFactor) + containers × writableLayer
overlay2 uses efficient page-level copy-on-write directly on modern kernels (4.0+), has minimal metadata overhead, and is the default in all modern Docker installations.
On older RHEL/CentOS systems without overlay filesystem support, devicemapper (direct-lvm mode) was the only production-ready option, but it has been deprecated in favor of overlay2.