I am not sure if you have already answered it and I have somehow missed it:
- Are these 'a' and 'b' on two different servers? ( I think they are on different servers)
- Did you stop the server on 'b' before you replaced the files and attempted a startup?
> thanks. it doesn't help. i also tried pg_ctl without luck (http://www.postgresql.org/docs/9.3/static/app-pg-ctl.html).
What exact pg_ctl command you used?
Regards
Sameer
