Win32 Backup errors

I've got a production 8.1.7.4 database that we're trying to back up over an SMB mount to a backup server with multiple TB of storage. The database server is a 4-way 16GB system running a ~250GB SAP system with 3 SAP application servers on the same host. We're using the /PAE and /3GB switches in the boot.ini.  

When we launch a backup we get the following error:  

RMAN-10035: exception raised in RPC: ORA-19502: write error on file "\\host\PRD\L0_95.2vi59kdt_1_1

OSD-04016: Error queuing an asynchronous I/O request.

O/S-Error: (OS 1450) Insufficient system resources exist to complete the requested service.

RMAN-10031: ORA-19624 occurred during call to DBMS_BACKUP_RESTORE.BACKUPPIECECREATE   Now I've found several links on the OS-1450 error indicating to provide the OS with more kernel memory. The interesting facts of the situation are:  

1. we can back up the entire database with 3 RMAN channels each using 15 files apiece, as long as we use local storage for the backup; as soon as we point it to the \\host <file:///\\host> system as a target, it blows up.
2. We can't even do a simple controlfile backup to \\host
   <file:///\\host> from this system.
   
3. We're able to run other backups of similar sized systems to \\host
   <file:///\\host> with no issues.
   
4. We're able to successfully backup to \\host <file:///\\host> if we start only Oracle after a warm boot; starting SAP while the backup is running causes it to terminate with the OS-1450 error.

If this is truly a system resource issue, I'd expect to see the paged & nonpaged kernel space decrease before the OS-1450 error is thrown; it's generated immediately however with no change in the kernel resources.  

The confusing thing is that with all of the SAP processes running, we can get a full backup with multiple channels to local storage, but it fails over the network (to any network share, not just \\host <file:///\\host> ).  

Anyone have any ideas on how to tackle this? I'm planning to try using the /userva switch in the boot.ini (described at http://support.microsoft.com/default.aspx?scid=kb;en-us;833721) this weekend to tweak the kernel memory settings. If that fails, then I'm going to try removing the /3GB switch and scaling back the shared memory requirements for the DB & SAP instances to see if that fixes the problem.  

Unfortunately, we're not able to upgrade to a 64-bit environment for several more months..  

Thanks for any insight,

Rich Holland

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