smtp / postfix?
 

Can't send mail with mail me@myaddress.com....

looked in /var/log/maillog and I see thousands of these....

Mar 14 07:46:42 server-01 postfix/smtp[9168]: fatal: open lock file pid/unix.smtp: file has 2 hard links
Mar 14 07:46:43 server-01 postfix/master[2099]: warning: process /usr/libexec/postfix/smtp pid 9168 exit status 1
Mar 14 07:46:43 server-01 postfix/master[2099]: warning: /usr/libexec/postfix/smtp: bad command startup -- throttling

Server is RHEL 6. Five others in this cluster work fine.... so not sure what happened here. I didn't really configure them any differently.

The error is here:
open lock file pid/unix.smtp: file has 2 hard links

You need to take a look at what those hard links actually are. Do an ls -i of the /proc/pid/unix.smtp file to get the inode number then do a find to look for that inode. find / -inum the inode number