How are you uniquely identifying CIs in your environment today?

[Suggy]

I always thought Serial number field could be used to uniquely identify a CI in the CMDB.

Even OOB Hardware identifier uses 'Serial number' in identifier entries. 

I was stumbled upon seeing this official article which says Serial number should not be considered as UNIQUE, and ServiceNow only giving OOB identifiers with Serial number as unique. 

The article at the end says use IRE rather than setting the serial number as unique.

Also we know that name can be duplicated, same with IP address, MAC address etc.

Then what on earth should we consider as unique to identify a CI? 😮

Please do let me know what you have considered as unique in your CMDB projects.

Thanks in advance!!!!

[Suggy]

Anyone

[Dr Atul G- LNG]

Hi @Suggy 

Practically there is not unique identifier on CI table like we have on Inc. / change which help us to identify. CI's are identified by the classes/ source / type etc, it may look wired but i think this only way.

[richardbrounste · Accepted solution]

While Serial number might technically be possible to be duplicated between servers and operating systems from different manufacturers, they are still a good mechanism for unique identification.

1. Serial numbers will not change once assigned.  IP Addresses and MAC Addresses (on virtual hardware) can change, which is why they are not reliable for unique identification.  Serial numbers don't change.

2. While it is theoretically possible that the serial number in a Linux OS to be the same as the serial number in a Windows OS or some other system, it is highly, highly, highly unlikely.  The odds are astronomical. So, you should consider that these serial numbers are unique.

That's all that's needed for a unique identifier.  You should feel safe with the serial number as long as the serial number can be queried....whether on Earth or any other planet.

[Suggy]

@richardbrounste  Thank you for replying 🙂

I have been marking serial number as unique at dictionary since many years and did not face any issue. But when I came across this article, I got little confused and worried 😄 

And yes I strongly believe that scenario is very highly unlikely to happen.