It is too slow for git sendmail.

15468

　　I used git server to manage my projects for a long time. It is so good so that I want to use it in a big environment. Now many people will join to the projects. Thus, I have to turn on the mail notice function to notify the members when a change has beendone on the projects. By default, git server uses sendmail to send mails.
　　        $ sudo apt-get install sendmail
　　Then I configured the project as following:
　　repo    testing
        config hooks.mailinglist  = members@domain.com
        config hooks.announcelist = members@domain.com
       config hooks.envelopesender = gitserver@domain.com
        RW+CD                     = @admin
        -     refs/tags/v[0-9]    = @all
        RWC   refs/tags/          = @all
        RW    master              = @all
        RW+CD refs/heads/u/USER/  = @all

　　Pleae note, if you don't set hooks.envelopesender, maybe some of the mail list memebers can't receive the mails.
　　
When I push the commit, it will take a long time, more two minutes to finish pushing. Then I found the issue was caused by sendmail. And I execute "cat /var/log/mail.err", it shows the following message:
　　Aug  6 11:22:43 T420i sendmail[4366]: unable to qualify my own domain name (localhost) -- using short name
Aug  6 11:23:58 T420i sendmail[4572]: My unqualified host name (localhost) unknown; sleeping for retry
　　So I opened the /etc/hosts file with "sudo vi /etc/hosts" command.
　　changed
　　127.0.0.1    localhost
　　into

　　127.0.0.1    localhost.org   localhost
　　Then I tried to push a new commit again. It works and fast to finish pushing.