To reduce the amount of time required for a virus scan, you can configure Powertech Antivirus for IBM i to perform a changes-only scan, which scans only objects created after the previous scan and objects changed since the previous scan.
A changes-only scan can be used by itself, or in combination with a full scan that rescans all objects, on a different day. The benefit of the full scan is that it can use more recent virus definition updates.

To enable changes-only scans, you must:

  • Configure the operating system
  • Configure the scan task

These steps can be performed at any time, as described below. They do not need to be performed immediately after installation.

Note: If both Powertech Antivirus for IBM i and Powertech Encryption for IBM i are installed, and if Powertech Encryption is used or is planned to be used to encrypt IFS files, the changes-only scan cannot be used, and the above steps should not be performed.

Configuring the Operating System for Changes-Only Scans

To configure the operating system for changes-only scans:

  • Ensure that system value QSCANFSCTL includes the value *USEOCOATR
  • Submit the following commands to run in batch and under a user profile that has *ALLOBJ special authority:

CHGATR OBJ('/’) ATR(*CRTOBJSCAN) VALUE(*CHGONLY) SUBTREE(*NONE)
CHGATR OBJ('/*') ATR(*SCAN) VALUE(*CHGONLY) SUBTREE(*ALL)

Note: A high number of CPFA0AD "Function not supported by file system" messages may appear in the job logs of the submitted jobs. This is normal and not an indication of an issue.

On-access scanning, if used, will immediately run in changes-only mode following the above steps, and will gain the performance benefits resulting from it. On-demand scanning, in contrast, will only benefit if they are parameterized accordingly. This is described in the following subsection.

Configuring the Scan Task

Each scan task can be configured to either perform a changes-only scan or a full scan. To configure a scan that only scans changed objects, ensure that the FORCE parameter of the scan contains neither the value *ALL nor the value *CHGONLY.

The next time that this scan task will be run, it will perform a changes-only scan.

Note: The duration of the first scan run on a system will not be shorter. Only subsequent scans will benefit from being configured as changes-only scans.