How to install phpredis extension on Centos6 using pecl:
# Enable EPEL repository
yum install epel-release
# Install Autoconf v2.68
yum install autoconf268
# Install the extension
PHP_AUTOCONF=autoconf268 PHP_AUTOHEADER=autoheader268 pecl install redisThen add extension=redis.so to php.ini. The output of php -i should include Redis Support => enabled