IBM Support

Using the SAV Command to Save Windows Files Using QNTC Performance Considerations

Troubleshooting


Problem

This document provides information about using the performance implications of saving files through QNTC versus saving local IBM i OS files.

Resolving The Problem

This document provides information about using the performance implications of saving files through QNTC versus saving local IBM i OS files.

There are two applications that run for a file level backup of the Microsoft Windows Server (using the SAV command issued on the System i). One application runs on the System i, and the other runs on the Windows Server. When you issue the SAV command through QNTC, you initiate a request to the Windows Server application to gather the information from the area specified in the SAV command (directories, files, and so on). That information is then sent back to the System i application. The System i application then saves that data to the tape drive specified.

Because of these differences, there are performance issues that should be noted:
o Benchmarks for all backups will vary based on the tape drive specifications.
o Benchmarks for QNTC with supported tape drives have seen results between 8GB (minimum) and 30GB (maximum) of data per hour.
o Newer tape drives have seen that minimum move up to 15GB (minimum) but still maintain the 30GB (maximum) of data per hour.
There have been various tests in which slight increases have been seen in the performance of the save by increasing the TCP attributes through the CHGTCPA command:

CHGTCPA TCPRCVBUF(xxxx) TCPSNDBUF(xxxx)

Note: The attributes for the TCP send and receive buffer sizes can range from 512 - 8388608 (in bytes).

Our testing has shown that there are no other performance ramifications for changing these values.

Further questions regarding the recommendations for backing up Windows Server information can be found in Chapter 7 of the Microsoft Windows Server 2003 Integration with iSeries IBM Redbooks which is available at the following Web site:

http://www.ibm.com/support/knowledgecenter/ssw_ibm_i_71/rzahq/flbackupsetup.htm

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Historical Number

452964584

Document Information

More support for:
IBM i

Component:
Integrated File System->QNTC

Software version:
All Versions

Operating system(s):
IBM i

Document number:
636613

Modified date:
22 April 2025

UID

nas8N1014325

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