Virtual machine optimization and/or storage reclamation solutions are disclosed that manage virtual machine sprawl and/or growing enterprise storage costs. For instance, certain solutions receive recommendations based on one or more rules, policies and/or user preferences that identify storage and/or alignment criteria for virtual machine disk (VMDK) partition(s). In certain examples, a resize tool that operates within a host operating system of a host server dynamically resizes and/or aligns one or more VMDK partitions of a powered-down virtual machine. For instance, the resize tool can be injected to the host server from a remote management server and can resize and/or align the VMDK partitions without requiring contents of the VMDK to be copied to another VMDK. By reallocating storage and/or aligning the VMDK partitions, embodiments of the invention can increase virtual machine performance and improve storage management.