Alert Zabbix database is down every 15 minutes

[gumis_148]

I got alert "Alert Zabbix database is down" every 15 minutes. What could be the reason?

/var/log/zabbix/zabbix_server.log:



And I get often logs from InnoDB (every 1 minute) /var/log/mysql/error.log:



/etc/mysql/my.cfg

root@zabbix:/home/appliance# cat /etc/mysql/my.cnf

[client]
port            = 3306
socket          = /var/run/mysqld/mysqld.sock

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

[mysqld]
user            = mysql
pid-file        = /var/run/mysqld/mysqld.pid
socket          = /var/run/mysqld/mysqld.sock
port            = 3306
basedir         = /usr
datadir         = /var/lib/mysql
tmpdir          = /tmp
lc-messages-dir = /usr/share/mysql
skip-external-locking

bind-address            = 0.0.0.0

max_allowed_packet      =1G
key_buffer              = 16M
thread_stack            = 192K
thread_cache_size       = 8
myisam-recover         = BACKUP
max_connections        = 500

query_cache_limit       = 100M
query_cache_size        = 100M

log_error = /var/log/mysql/error.log
                       = /var/log/mysql/mysql-bin.log
expire_logs_days        = 10
max_binlog_size         = 100M

[mysqldump]
quick
quote-names
max_allowed_packet      = 16M

[isamchk]
key_buffer              = 16M