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?

[palmen]

We are using 5 instances

Education, Development, Test, Production Test, Production

Education: It's our sandbox and it's ok to clone it without notice. We also use it as a verification environment after every release.

Development: All our development is done here

Test: We use it for all system tests and to verify all our update sets and merged upsate sets work.

Production Test: Final acceptance testing is done by our end users. We use it to simulate the deployment to production

Production: Explains itself

In my oppinion we need at least 4 instances. We could live without the Test instance.

The night before every release we make a clone of our production instance to Education instance. It's vital for us to have a reference instance to verify how it was before a deployment in case someone find a defect/feature after deployment.

[Deepak Ingale1]

Thanks Fredrik for a reply.

You are very lucky to have this kind of setup. But our case is totally different. We have only two instances. Now problem is, for every development we do in DEV, we need to export it to our PC. Clone the PROD to DEV, import whatever updates were exported, do testing. One done we need to migrate it to PROD. This I think is very risky because you skip the step of testing updates i.e. if update sets get imported succssfully. Whether merging operation has happened successfully etc.

I want reviews from experts who have faced this issue with two instances and how they have overcome it. Also if two instances are very risky thing to have, what strong points are needed to convey management to go for third one.

[Kalaiarasan Pus]

3 instances is a must per me... There are chances that we might miss capturing the some updates if we are working in a multi member team ... Test environment is for that purpose.. Testing the updates before we move the changes to the real world.. This would help us eliminate few mistakes/bugs before they impact the prod environment.. We even many a times had requirement changes when the clients test on our 'test' environment and asking few changes to be made before the final deployment..

All in all, I would say that there is no harm in having a three instance setup

[Anurag Tripathi]

I would second Kalai here.

Minimum 3 instance should be there....DEV -> UAT -> Prod

At the same time i would say 4 instance setup will be more optimum as chances of failures on production can be controlled very efficiently.