ProxySet: unknown lbmethod lbmethod=byrequests; balancer://mycluster

apache2 error : While creating Load Balancer
ProxySet: unknown lbmethod lbmethod=byrequests; balancer://mycluster

If you are getting above error after setting Load Balancer in your conf file while restarting apache, you need to enable following module in apache.

Run following command 

sudo a2enmod lbmethod_byrequests

Now Restart apache.

Not able to find sendmail log

If you are not able to see log in /var/log/mail.log and file is empty, check the mail logs in /var/log/syslog

tail -n 25 /var/log/syslog

pecl install stomp error

configure: error: Cannot find OpenSSL's libraries
ERROR: `/var/tmp/stomp/configure --with-openssl-dir=/usr' failed

Solution :
While installing stomp using pecl, it asks
OpenSSL install prefix (no to disable SSL support) [/usr] :
Type yes and press return key.

Do not leave the input blank.