Tape streaming is not happening while performing RMAN tape backup. On investigation, you
find that it is not because of the incremental backup or the empty file backup and that RMAN
is sending data blocks to the tape drive fast enough.
What could be a solution to make tape streaming happen during the backup?
A.
Configure backup optimization
B.
Configure the channel to increase MAXOPENFILES
C.
Configure the channel to increase the capacity with the RATE parameter
D.
Configure the channel to adjust the tape buffer size with the BLKSIZE option
I think its D
https://docs.oracle.com/cd/B10501_01/server.920/a96566/rcmtunin.htm#449982
Please note that the version of oracle examened in the sxam IZO-053 is 11.2.0.1 as stated here
https://education.oracle.com/pls/web_prod-plq-dad/db_pages.getpage?page_id=5001&get_params=p_exam_id:1Z0-053&p_org_id=&lang=
Therefore please refer to the documentation found in
https://docs.oracle.com/cd/E11882_01/index.htm
This documentation is as of version 11.2.0.4 but it is the closest to 11.2.0.1 as can be found on an official website.
C seem to be the correct answer :
http://docs.oracle.com/cd/B28359_01/backup.111/b28270/rcmtunin.htm#BRADV90071
Rate can define the bytes/second that are read on a channel and it is necessary to slow down the transmission of data
It reads, “RMAN is sending data blocks to the tape drive fast enough” meaning that the RATE parameter is pushing/configure fast enough. Increasing the blksize parameter will stream faster. Norberto is dead-on.
Note that the RATE parameter doesn’t improve performance but throttles
performance intentionally to limit the disk bandwidth available to a channel. This
is useful when your RMAN backups must occur during periods of peak activity
elsewhere in the database.
Trcky Question….I opt for D
Use the BLKSIZE Parameter to Alter Tape Buffer Size
If the tape is not streaming, but the problem is not due to an incremental backup or by backing up empty files, then you can try adjusting the block size of the tape buffer. You can change the size of each tape buffer using the PARMS parameter of the ALLOCATE CHANNEL or CONFIGURE CHANNEL command. If the BLKSIZE parameter for PARMS is supported on your platform, then you can set it to the desired size of each buffer. For example, configure an sbt channel as follows:
CONFIGURE CHANNEL DEVICE TYPE sbt PARMS=”BLKSIZE=524288″;
A good rule of thumb is to set BLKSIZE to a value that is a little less than the tape block size of the media manager. What “a little less” means depends on the media manager. For example, if the tape block size is 512 KB and the media manager has a header of size 16 KB, then you can set BLKSIZE=49600.
Note that it is also a good idea to increase the media management physical tape block size. For example, you do not want to set the BLKSIZE parameter to 512 KB and leave the physical tape block size as 32 KB.
Please note that the version of oracle examened in the sxam IZO-053 is 11.2.0.1 as stated here
https://education.oracle.com/pls/web_prod-plq-dad/db_pages.getpage?page_id=5001&get_params=p_exam_id:1Z0-053&p_org_id=&lang=
Therefore please refer to the documentation found in
https://docs.oracle.com/cd/E11882_01/index.htm
This documentation is as of version 11.2.0.4 but it is the closest to 11.2.0.1 as can be found on an official website.
I think the answer is B or D.
For answer B …
Increasing the smallest of these variables will increase multiplexing and therefore data transfer rates.
multiplexing_level = MIN of
– MAXOPENFILES (defaults to 8)
– FILESPERSET (defaults to 64, but recommended to use 8 or less for recovery performance),
– FILES_PER_CHANNEL
For answer D …
@Magwai, your comments make a lot of sense. Thanx
As for C you should avoid sing RATE (supossedly deprecated in 11.2) or DURATION if you have problems streaming.
Thanks for the comments!
I also vote for D.