If Russian citizen, has a EU spouse (traveling together) and Swedish permanent residency. Does he/she still required a visa to Ireland?
Family member of EU national: If you are a non-EEA national coming to Ireland from another EU country as a dependant of an EU national, and you do not hold a document called "Residence card of a family member of a Union citizen", you may need a visa when you first travel to Ireland.
how to get this Residence card of a family member of a Union citizen ?
"you may need a visa"... may not?
https://en.wikipedia.org/wiki/Residence_card_of_a_family_member_of_a_Union_citizen
Implementation in Ireland
Ireland calls its Residence Card Stamp 4EUFam (EU Directive 2004/38/EC). Ireland has now implemented this part of the directive in full according with the Immigration Act 2004 (Visas) Order 2011 and consequently it is now possible for family members to gain entry into Ireland with a residence card issued by any member state.[6]