What is the difference between vmfssparse and thin?

[cai123]

I see there is a saying that the snapshot uses vmfsspare, and the creation of virtual machine disks can be thick or thin. Both thin and vmfsspare volumes are dynamically expanded according to usage, but I don't understand the detailed distinctions.

[Joffer77]

The key difference between vmfssparse and thin lies in what they are used for and how they manage disk space in VMware:

Thin provisioned VMDK are used for normal VM virtual disks, and allocates disk space on demand, only as data is written. It can grow up to the configured size (e.g., 100 GB) as needed and is your day-to-day storage savings for VM disks.

vmfssparse (also known as delta), are used for snapshots and linked clones. It only stores the changes made since the snapshot was taken, and is a temporary disk to track VM changes during snapshot lifecycle.

A VM with a snapshot has a vmfssparse child disk layered over a base disk (which may itself be thin, thick, or eager zeroed). You should not manually modify or move vmfssparse disks.

[a_p_]

Other than "Thin Provisioning", which is a file system feature, "vmfssparse" is just file based, where the .vmdk file contains metadata (pointers) in addition to the user data.

André

[cai ts]

thanks;