sorry againa and again
i forgot one line again i have this line in my csupdate location too'
proxy_redirect http://192.168.1.1/csupdate http://nx.chare.ir/csupdate;

my csupdate location is like this finally :

location /csupdate {
proxy_pass http://mysites_hash/csupdate;
proxy_set_header Host 192.168.1.1;
proxy_redirect http://192.168.1.1/csupdate http://nx.chare.ir/csupdate;
}

but this works when i have only one server in mysites_has upstream