Discovery updating and creating new record

[yash755]

Hello all,

I have a query regarding identifier rules. Suppose I have two identifier rules.
Rule 1: It checks the uniqueness of the serial number
Rule 2: It checks the uniqueness of the name

Now, suppose a discovery run and brings some CIs. 
So, CI will first look for rule 1. 
So what will happen if the serial number is the same and what will happen if it's different?

When will it go to rule 2? 

When will be the same record updated and when will the new record create?

[johnnyjava · Accepted solution]

It should look at the second entry (1 rule, multiple entries) when / if the fields (criterion attributes) for the 1st entry aren't present. So name will be considered when the serial_number is missing. (I see this happen for network devices on very busy network segments where the SNMP traffic is sometimes dropped. You can tune the SNMP disco settings to have it wait longer or repeat attempts.)

As long as the Identification and Reconciliation Engine can locate a record that matches by one of the entries for that class of device / application server, then it will update the existing record. If there is no match, but there are matchable attributes then a new record will be created.

If there's more than 1 matching record, it should mark the newest of them as a Discovery source = Duplicate.

[yash755]

Just to summarise everything.

First, go to Rule 1.

1. If the serial is present and unique create a new record.
2. If the serial number is same then update the record.
3. If multiple CIs with the same thing the marked duplicate.
4. If the serial number is empty go to Rule 2

Now if we go to Rule 2 and follow the same procedure. And we will go to Rule 3 when Rule 2 fields are empty.

[richardbrounste]

And if the serial number is the same, it will overwrite the CI.  If there are 2 or more CIs with the same serial number, it will mark them as duplicates.  Check out this article on how we use the identification rules to find duplicates:  https://community.servicenow.com/community?id=community_blog&sys_id=3efc66a5dbd0dbc01dcaf3231f96193b

[yash755]

So when will it go to Rule 2?