The scanner parallelization feature increases scan speed making a scan up to four times faster, depending on the size of your network, while maintaining scan accuracy. Using this feature a scan task is distributed to a pool of five scanner appliances thus improving scan performance, when the scan target includes asset groups. The scanner parallelization option is available for on demand and scheduled scans when the scan target includes asset groups. If you wish to submit a scan task on individual IP addresses instead of asset groups, one or more scanner appliances must be applied to the task. Scanner parallelization is supported for both vulnerability scans and compliance scans.
When enabled for a scan task at scan time, the task is distributed to multiple scanner appliances in parallel for each target asset group. The top five scanner appliances listed in each asset group make up the pool of scanners used to scan the group's IP addresses. At the completion of the scan, the service compiles a single report with scan results.
During scan processing, if a scanner appliance is not available for some reason, perhaps because it is offline, the service automatically distributes the scan task to another appliance in the scanner appliance pool for the asset group.
Note that a scan task can only be distributed across scanner appliances that have the same vulnerability signatures version and the same scanning engine version at the time of the scan. You can view version information for a scanner appliance from the scanner appliances list (Tools > Scanner Appliances). If one of the scanner appliances in the pool has a version that does not match the other scanner appliances, it will not be used as this may have a deleterious effect on reporting. If some scanner appliances have identical versions and others do not, then the appliances with the most matching versions are used, regardless if the software is not as current. For example, if 3 scanners have the same vulnerability signatures and scanning engine versions and the other 2 scanners have a different version, then the 3 matching scanners are used.