Hi,
Yes it is possible to apply QOS on the internet links used for IPSEC. You can refer to below as an example. I assumed you created IPSEC tunnels using Cisco ISRs.
HO:
!!!! Internet Interface - used for IPSEC Conection )
Interface gi0/0/0
bandwidth ( actual bandiwdth provided by ISP )
!!!! put your server address on the source of below ACL
access list 101
permit ip any x.x.x.x any
class-map SERVER
match access-group 101
policy-map P-SERVER
class SERVER
priority 2000
!
Interface gi0/0/0
service-policy output P-SERVER
Branch:
!!!! Internet Interface - used for IPSEC Conection )
Interface gi0/0/0
bandwidth ( actual bandiwdth provided by ISP )
!!!! put your server address on the destination of below ACL
access list 101
permit ip host any x.x.x.x
class-map SERVER
match access-group 101
policy-map P-SERVER
class SERVER
priority 2000
!
Interface gi0/0/0
service-policy output P-SERVER
hope above will help full to you!