Mladen,
Ram,
The data will stream between the database server and the media server,
regardless if you start rman from that server or from a "client".
On the db server the server processes will handover the data stream to
the NB library, which sends it to the configured media server.
regards,
Freek
On di, 2015-04-21 at 23:55 -0400, Mladen Gogala wrote:
Ram, if you connect to the database using Oracle*Net, as in rman
target sys/<passwd>@<TNS> amd allocate channel device type SBT, the
backup will actually be streamed from that client computer to the
backup software. When rman allocates channel of type SBT it maps
libobk.so into its address space. The proposition was to have this
library on a single machine, so that it can connect to multiple
databases. Since that library implements calls like sbtwrite and
sbtwrite2, which are used to send data to backup software, the machine
on which that library resides would necessarily become a communication
point between all the databases and the backup software. Thus, it
would become a single point of failure, too.
On 04/21/2015 10:43 PM, Ram Raman wrote:
Mladen or anyone else, can you explain <q>Adding the 3rd network
point can severely impact the performance, since all the
communication would actually go through that dedicated "backup
server"</q>
I would think that the backups themselves would still run on the
database servers (isn't that where the rman and oracle binaries and
db files are located) and the backups would still be using the DB
servers' CPU. The 'backup server' in this scenario may only have to
communicate with each db server and initiate the backups on a
nightly basis. Am I right in my assumption? If that is correct
there will not be too much data flowing between the DB servers and
the backup server; the backup server will not be a big bottleneck.
Reason I am asking is Seth's idea looks great to me, but would like
to know if the backup server would be a limiting factor. Also if
anyone has such a setup they can share their experiences.
Thanks
Ram.
If you like your shell scripts and are comfortable
with cron, you might be able to just enhance it
enough to eliminate the single point of failure and
dramatically reduce your risks by centralizing your
backups.
Modify your rman scripts to use an Oracle wallet to
authenticate to the databases remotely through an
rman client. That way, you can take a backup without
having to be on the server and won't expose the
password of a privileged account.
What about performance? NetBackup usually pushes the data
from DB server to media server. Adding the 3rd network point
can severely impact the performance, since all the
communication would actually go through that dedicated
"backup server". What happens if there are several
simultaneous backups, all going through the "backup server"?
Do you need to backup all the databases at separate times?
RMAN maps libobk.so into its address space at the time when
"allocate channel device type SBT" is executed and it's
libobk.so which facilitates the communication between rman
and the media server. So, all communication for database
backups would go through this "backup server", which would
not only be a bottleneck, but also a single point of
failure.
--
Mladen Gogala
Oracle DBA
http://mgogala.freehostia.com
