Using Files in a ZFS Storage Pool

With ZFS, you can use files as virtual devices in your storage pool. If you adopt this method, ensure that all files are specified as complete paths and are at least 64 MB in size.

This feature is useful for testing, such as experimenting with more complicated ZFS configurations when physical devices are insufficient. Do not use this feature in a production environment.

If you create a ZFS pool backed by files on a UFS file system, then you are implicitly relying on UFS to guarantee correctness and synchronous semantics. However, creating a ZFS pool backed by files or volumes that are created on another ZFS pool might cause a system deadlock or panic.