How to increase a number of nfsd threads in pcs/corosync environment?

I have NFS server bound with *pcs/corosync* to provide stability and HA. The default number of nfsd threads is 8, wich I find too little as I can observe that mostly all 8 are 90% busy all the time. The nfs/corosync/pcs system consists of 3 servers and a dist storage. How can I increase a number of threads: should I modify */etc/sysconfig/nfs* file on all NFS nodes or should I make some changes somewhere else? Sorry for newbie question but I have nobody to ask for it. Appreciate any help, thank you. OS: Centos 7.