05-22-2015 04:18 AM
our database team triggered rman restore with 4 channels, but 1 restore channel is running out of 4 and the remaining are ideal. Please let me know how to run 4 restore channesl at time and 4 channels are in different media.
we have engouh drives and enable media multiplexing, but only 1 streem is running.please let me know is there any way to make the other streams to run.
Solved! Go to Solution.
05-23-2015 01:09 AM
It depends how your data has been written. If you've used multiplexing to do the backup (which is not good) then you'll not be able to read 4 streams simultaneously.
If you've not written the backups with multiplexing, and you've used 4 drives to store the data on 4 media then you should not face this issue.
Please confirm.
Do the streams that are queued say something like "waiting for media xxxxxx" " media in use"?
What does the status inside those jobs say?
05-23-2015 04:49 AM
How many rman channels was allocated when doing the backup ? my guess would be one
You get the best performance if you allocate the same number of rman channels for the restore as the backup was written with.
To restore from 4 different media, you need 4 channels writing to each their own tape drive when doing the backup, which means you cannot use multiplexing on the tape drives.
05-23-2015 01:09 AM
It depends how your data has been written. If you've used multiplexing to do the backup (which is not good) then you'll not be able to read 4 streams simultaneously.
If you've not written the backups with multiplexing, and you've used 4 drives to store the data on 4 media then you should not face this issue.
Please confirm.
Do the streams that are queued say something like "waiting for media xxxxxx" " media in use"?
What does the status inside those jobs say?
05-23-2015 02:29 AM
05-23-2015 04:49 AM
How many rman channels was allocated when doing the backup ? my guess would be one
You get the best performance if you allocate the same number of rman channels for the restore as the backup was written with.
To restore from 4 different media, you need 4 channels writing to each their own tape drive when doing the backup, which means you cannot use multiplexing on the tape drives.