Tuesday, February 4, 2014

RAC-- RMAN CHANNELS MULTI NODE

In RAC environments (Eg Exadata), we use high parallel processes for RMAN backup, we use high count of channel and etc. We also use high parallel IO devices like DBFS_DG to increase the speed of our rman backups.. In this context, it is also useful to use all the RAC nodes for parallelizing the backup process.. In other words; it is useful to spread the rman backup processes accross the RAC nodes to maximize the processing performance..

In order to do that, we can use manual channel allocations;
I mean, we can direct rman to allocate a channel through node 1 and allocate another channel through node2 and etc.. Like the example below;

CONFIGURE CHANNEL 1.. CONNECT 'user1/pwd1@node1'; 
CONFIGURE CHANNEL 2.. CONNECT 'user2/pwd2@node2'; 
CONFIGURE CHANNEL 3.. CONNECT 'user3/pwd3@node3';

In addition, you can use automatic channel allocation in RMAN to load balance the channels automatically.
In order to do that, you can configure your channel type to connect to the target using LOAD BALANCED service name, which is present in your tnsnames.ora.

CONFIGURE CHANNEL DEVICE TYPE DISK CONNECT 'user1/pwd1@<service_name>'

By setting this, parallel rman backup workers will  be automatically spreaded across rac database node without manual channel specification..

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