Is the oracle server also a media server?  If not, I have seen this due to 
Solaris network drivers.  Although it is odd that your OS backups run at 
100MB/s, I never saw that.  Backing up Solaris across a gigabit network I 
was never able to exceed 60 MB/s whether it was Oracle or OS data.

I confirmed the bottleneck was solaris by using netcat.  I saw this on 
Solaris 8 and 9 on sparc hardware with both ce and ge interfaces.  The ce 
interfaces are about 10MB/s faster, but not more than 60 MB/s total.

I'm told Solaris 10 on x86 does not have this problem but I have not tried 
it.

If your Oracle server is a media server, my only guess is internal RMAN 
throttling.  I'm not a DBA, I don't know how to check for this and I don't 
see it in the RMAN Pocket Reference, so check with your DBA.


----Original message----
Date: Wed, 4 Oct 2006 09:15:05 +0500
From: "Atif Munir" <atif76 at gmail.com>

I am using netbackup 5.1 with rman for my oracle database backups.OS is
Solaris 9 with oracle 9.2.0.7 and I am unable to get a speed more than
50MB/sec. For FS backup this speed is 100MB/sec but for rman I get
stucked at 50MB/sec. I don't know why I am unable to get more speed.

The library is L100 and I am using two drives for backup. By increasing
number of drives or number of channels the backup speed is not going to
be better.


The tunning I have made so far is.


NET_BUFFER_SZ as 262144
NUMBER_DATA_BUFFERS=64
SIZE_DATA_BUFFERS=1048576


-- 
Joe Royer / SysAdmin / Digital Motorworks / 512-692-1028


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