Two instances vs three instaces model?

[Deepak Ingale1]

Hello,

We are migrating to MSP solution in domain separation. For that we just purchased ServiceNow instances. We are given two instances. One   as a "DEV" and another one as "PROD" instance.

I find this very challenging to manage considering development , upgrade etc to be done in same DEV instance and then move changes to PROD without having a middle test instance (DEV--> TEST --> PROD ).

Normally there should be minimum three instances for the proper development and upgrade point of view.

1) keep DEV for development,.

2) clone your PROD to TEST to have a mirror copy.

3) move DEV updates to TEST and perform UAT kind of stuff and overall testing before finally moving those updates to PROD.

This three level setup will also come in handy when there is an upgrade release from SN for hotfix, patches etc.

I am finding this really challenging to manage all this with only two instances.

Can some one provide their expertise on how to manage with two instances. Or should I convince my management to purchase third instance as well which will be a TEST. If that is a case what strong points should I suggest them?

[Uncle Rob]

That can work in general, but people should be aware that Testing Installation must, by necessity, be after UAT.     If your users found defects that need to be addressed before go-live, you need more update sets, and therefore a second battery of installation testing.   The only way I figure this can be facilitated on one Test instance is if you Clone immediately after UAT.   That's great if you deal with all development in single file... but I've never been on an account that does.