What are disadvantages to storage directly attached to the application servers?

What are disadvantages to storage directly attached to the application servers? (Choose three.)

A.
reliability

B.
scalability

C.
redundancy

D.
manageability

Explanation:
B: System administrators are faced with the challenging task to managing storage and making it
scalable to accommodate future needs.
With storage directly attached to the server, scalability is difficult. The storage expansion capability
is limited to the capacity of the server (for example, as measured by the number of I/O controllers
and devices per controller configured is the server). The nature of the small computer system
(SCSI) bus commonly used to connect commodity disks to a commodity server makes it difficult to
allocate more disk storage without interrupting and rebooting the server, and thus affecting
applications.
C: No redundancy is provided

Reference: Arch student guide p.13-6.