Hi,

Currently we are migrating from SharePoint 2010 to SharePoint 2013,

2010 application is on Classic based authentication and we require the 2013 application to be in Claims mode of authentication.

Which option would be better?

1. Convert the 2010 application to Claims and then migrate
2. Migrate as it is to 2013 with Classic and then convert it to Claims

Also, if we do not migrate it to Claims based authentication, what are the impacts.

Please suggest,

Thanks,

Sachin

If you don't convert to Claims authentication then you won't be able to use some things like OWA and the remainder of SharePoint may or may not work. SP 2013 does have some ability to work in the Classic mode but it's not something you want to run with over a long period.

Both options have advantages, from my experience option 1 is slightly less error prone however it makes rolling back a lot harder. For that reason option 2 is the most common approach.

Its usually less work to convert the 2010 application before migrating it to 2013.  But doing so risks downtime on the 2010 environment if things don't go well.  So for most of the projects that I've worked on we do the migration first and then convert it to Claims.

+1 on migration first, then convert to claims. It will also be faster than 2010 if you're running 2013 SP1 + April 2014 CU or higher (would recommend something like the May 2015 CU).

I have had less issues when converting first. Im not sure I understand the concern about "rolling-back" unless there is some need to have your 2010 in classic. As a general rule I almsot always convert 2010 classic to claims regardless of upgrade desires.

You have a 2010 farm in a known, good state. Not all services in 2010 are claims compatible. If anything goes wrong during the upgrade that requires a roll back, it is significantly more desirable to have a farm in a known, good state to go back to.

Not to mention conversion under 2013 is significantly faster. You can also just create the 2013 Web App in Claims, and use Convert-SPWebApplication when you connect classic databases. You don't have to drop to PowerShell to create a classic web app.

"Not all services in 2010 are claims compatible"

Which services in 2010 have issues with claims?

IFS, Visio, PowerPivot come to mind.