Are the other databases backed up to the same nfs mount ? As far as I know oracle does support netapp, others I don't know about. The requirements for the backup pieces and the datafiles will be the same.
With these settings was the backup speed per sec the same or longer.
mount -o hard,rw,noac,rsize=32768,wsize=32768,suid,proto=tcp,vers=3
When I changed the mount options to rsize=32768,wsize=32768, hard, noac,
my backup speed when from 9MB per second to 316KB per second.
Plus all of my Oracle 9i backup to the same NFS mounts were slower too.
The problem is the same issue. Performance was very poor. A database backup to local disks took 3 minutes. The same backup to NFS mounted disk with rsize and wsize set to 32768, 16384, or 1048576 was 1 hour and 9 minutes.
After many days and many test runs, Oracle Tech Support and I finally found the solution that work for me. rw,bg,intr,hard,timeo=600,wsize=32768,rsize=32768,nfsver=3,tcp
Now my backups to local disks and to NFS mounted disk are the same.
For the backup that took 3 minutes to local disks and the same backup to NFS mounted disk took 1 hour and 9 minutes, both now take 3 minutes.
This solution works with no adverse affect on my Oracle9i RMAN backups to the same NFS mounted disks.