Percona Mysql configurantion for a 4GB VPS

my.cnf

[mysqld_safe]
socket                          = /var/run/mysqld/mysqld.sock
nice                            = 0

[mysql]

# CLIENT #
port                            = 3306
socket                          = /var/run/mysqld/mysqld.sock

[mysqld]

# GENERAL #
user                            = mysql
default-storage-engine          = InnoDB
socket                          = /var/run/mysqld/mysqld.sock
pid-file                        = /var/run/mysqld/mysqld.pid
skip-external-locking
#
# Instead of skip-networking the default is now to listen only on
# localhost which is more compatible and is not less secure.
bind-address                    = 127.0.0.1
skip-name-resolve

# MyISAM #
key-buffer-size                 = 32M
myisam-recover                  = FORCE,BACKUP

# SAFETY #
max-allowed-packet              = 16M
max-connect-errors              = 1000000

# DATA STORAGE #
datadir                         = /var/lib/mysql
basedir                         = /usr
tmpdir                          = /tmp
lc-messages-dir                 = /usr/share/mysql

# BINARY LOGGING #
log-bin                        = /var/lib/mysql/mysql-bin
expire-logs-days               = 14
sync-binlog                    = 1


# CACHES AND LIMITS #
tmp-table-size                 = 32M
max-heap-table-size            = 32M
query-cache-type               = 0
query-cache-size               = 0
max-connections                = 500
thread-cache-size              = 50
open-files-limit               = 65535
table-definition-cache         = 1024
table-open-cache               = 2048

# INNODB #
innodb-flush-method            = O_DIRECT
innodb-log-files-in-group      = 2
innodb-log-file-size           = 128M
innodb-flush-log-at-trx-commit = 1
innodb-file-per-table          = 1
innodb-buffer-pool-size        = 1G

# LOGGING #
log-error                      = /var/log/mysql-error.log
log-queries-not-using-indexes  = 1
# enable only to debug
# SET GLOBAL slow_query_log = 'ON'; and FLUSH LOGS;
slow-query-log                 = 0
long_query_time                = 2
slow-query-log-file            = /var/lib/mysql/mysql-slow.log