# What Are the Restrictions for Attaching a Disk to a BMS?

- The disk and the target BMS must be located in the same AZ.
- The BMS must be in Running or Stopped state.
- Device Type of the EVS disk must be SCSI.
- A non-shared EVS disk must be in Available state.

  A shared EVS disk must be in In-use or Available state.

- BMSs using some flavors or images cannot have EVS disks attached because the servers do not have SDI iNICs or for other reasons.

Parent topic: Disk FAQ