Re: rman backup to tape
- From: Jared Still <jkstill@xxxxxxxxx>
- To: nagaraj.chk@xxxxxxxxx
- Date: Wed, 6 Jan 2010 09:01:16 -0800
On Wed, Jan 6, 2010 at 5:32 AM, Nagaraj S <nagaraj.chk@xxxxxxxxx> wrote:
> Good Morning All,
>
>
> I have clarification on rman backup to tape. Suppose if backup team
> increase the netbackup streams from 2 to 8, will it decrease the database
> backup completion time window? And also how to make changes on rman script
> to configure the new streams build by backup team and how rman can
> communicate to backup each stream data’s on each tapes separately... Thank
> You
>
>
If there are 8 drives available, then it may decrease the time required for
a backup.
If the network from the server to the tape library doesn't have the
bandwidth to
accommodate that much data, then the backups may actually take longer than
with 2 drives.
This is because tapes must be kept streaming to be efficient.
When tape drives run out of data to write, they stop and rewind.
When more data needs to be written, the tape drive must then
seek to where it left of writing.
Here's an article on the topic:
http://www.computerworld.com/s/article/93057/Slow_down_those_streaming_tape_drives
Increasing the number of drives in use will also make those drives
unavailable for other backup jobs.
Increasing the number of drives will also increase the number of tapes
that must be vaulted (sent offsite)
The real question is: Did the backup team do their homework when
deciding to increase the number of drives from 2 to 8?
Jared Still
Certifiable Oracle DBA and Part Time Perl Evangelist
Oracle Blog: http://jkstill.blogspot.com
Home Page: http://jaredstill.com
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