gigabytes respectively. `directory` optionally specifies the directory
in which to create the file backing the drive. `options` optionally
specifies extra comma-delimited properties which are passed verbatim
- to **qemu**'s `-drive` option. `file-id` specifies the ID of the file
+ to **qemu**'s `-blockdev` option. `file-id` specifies the ID of the file
backing the drive. Drives with the same file ID will share the
backing file. The directory and size of the file will be determined
from the first drive with a given file ID.