We have two FAS servers running on Vmware and two ...
# citrix-vads
Srinivasan Shanmugam
05/12/2026, 9:48 PMWe have two FAS servers running on Vmware and two new FAS servers deployed on XenServer. We have two GPOs with FAS config - one for VDAs and one for StoreFront servers. Any suggestions on migrating from old to new FAS servers without end user impact?
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Rob Zylowski
05/13/2026, 12:34 PMIf you can upgrade to 2511 before you do the upgarde it will be much easier because you can change to v2 toicketing which wont be dependent on the gpo for indexes to be correct to switch to the new serers. The hard part about switching fas server is keeping the index number consistent.
Check v2 ticketing here
https://docs.citrix.com/en-us/federated-authentication-service/2511/federated-authentication-service.pdf
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langsbr
05/13/2026, 1:34 PM@Rob Zylowski, is only FAS 2511 required for that, or does the site(s) need to be on 2511 as well?
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Rob Zylowski
05/13/2026, 1:46 PMGood point the VDA also needs to be 2511 or later
Rob Zylowski
05/13/2026, 1:58 PMSo then back to the original question the hard part is keeping the gpos consistent. pre 2511 the index values the vda sees must exactly match what the storefront and fas server see. So the hard part about changing the FAs servers is the timing around updating the gpo settings on the different machines. One thing you should definitely do is to enable the setting on storefront for fas failover. See
FederatedAuthenticationServiceFailovers
Srinivasan Shanmugam
05/13/2026, 2:02 PMVDAs have 4 indexes - fas1, fas2, fas3, fas4
fas 1 & 2 - datacenter 1
fas 3 & 4 - datacenter 2
Storefront in datacenter 1:
fas1, fas2, blank, blank
Storefront in datacenter 2:
blank, blank, fas3, fas4
Srinivasan Shanmugam
05/13/2026, 2:04 PMTentative plan:
1. Place fas2 in maintenance mode
2. Update VDA GPOs as fas1, newfas2, fas3, fas4
3. Once VDA have new fas list updated, modify registry or GPO for Storefront in datacenter 1 as fas1, newfas2, blank, blank
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Rob Zylowski
05/13/2026, 2:08 PMThats fine the question is how you swap out and in the new servers timing wise. As soon as you swap the servers on the storefront and fas servers you need to also have the gpos updated on the VDAs. This normally takes a little time. I woudl roll out the new servers in the vda gpos adding them at the end sp positions 5,6,7,8 and then when all teh vdas have tjhose you can update your fas and storefornt gpos to use them.
Rob Zylowski
05/13/2026, 2:09 PMthen just keep those gpos wiht more blanks until you upgarde past 2511 and the vda gpos dont matter anymore
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