mysql server has gone away

[johntest]

hi folks

this one is becoming a really annoying issue

here is the setup
zabbix connects to mysql via haproxy which resides locally on zabbix
mysql server is remote but on same network
everything is on same virtual network under vmware. same subnet etc.

Error
18172:20150806:191330.662 [Z3005] query failed: [2006] MySQL server has gone away [select hostid,status from hosts where host='Zabbix server' and status in (0,1) and flags<>2 and proxy_hostid is null]

Now in this case host "Zabbix server" does not exist. Or rather I renamed the host and changed the IP etc so its called "DC1 zabbix server".

haproxy.cfg (generous timeout settings)
retries 3
timeout queue 45s
timeout connect 60s
timeout client 5m
timeout server 5m
timeout check 30s
maxconn 1020

## on mysql server
/etc/my.cnf
wait_timeout = 28000
max_allowed_packet = 64M
max_connections = 512
join_buffer_size=300
table_open_cache=2500
innodb_buffer_pool_instances=1
innodb_buffer_pool_size=2G
query_cache_type=1
query_cache_size=128M

## zabbix_server.conf
CacheSize = 128M
Timeout=30
Timeout=29 (on agent node)
ValueCacheSize=128M
StartPollers=100
StartDBSyncers = 8

A related question:
If this issue happens and zabbix d/c with mysql. Does it re estalish connection immediatley without data loss?

So any ways to fix this? Would this cause any issues around losing monitoring data? How can we fix it ?

Thank you!