The BACKUP_TAPE_IO_SLAVES parameter is set to FALSE for the database instance.
Which statement is true while performing a tape backup in an RMAN session?
A.
The tape I/O performed is asynchronous
B.
The tape buffer is allocated from the System Global Area (SGA)
C.
The tape buffer is allocated from the Program Global Area (PGA)
D.
Oracle I/O uses an interrupt mechanism to determine when each I/O completes
Explanation:
Tape I/O Slaves
RMAN allocates the tape buffers in the System Global Area (SGA) or the Program Global Area (PGA),
depending on whether I/O slaves are used. If you set the initialization parameter
BACKUP_TAPE_IO_SLAVES=true, then RMAN allocates tape buffers from the SGA. Tape devices can only be
accessed by one process at a time, so RMAN starts as many slaves as necessary for the number of tape
devices. If the LARGE_POOL_SIZE initialization parameter is also set, then RMAN allocates buffers from the
large pool. If you set BACKUP_TAPE_IO_SLAVES=false, then RMAN allocates the buffers from the PGA.
If you use I/O slaves, then set the LARGE_POOL_SIZE initialization parameter to dedicate SGA memory to
holding these large memory allocations. This parameter prevents RMAN I/O buffers from competing with the
library cache for SGA memory. If I/O slaves for tape I/O were requested but there is not enough space in the
SGA for them, slaves are not used, and a message appears in the alert log.
The parameter BACKUP_TAPE_IO_SLAVES specifies whether RMAN uses slave processes rather than the
number of slave processes. Tape devices can only be accessed by one process at a time, and RMAN uses the
number of slaves necessary for the number of tape devices.