Zabbix agent log says "Only the first 64 kB will be analyzed." for large log record.
It should be corrected to 256 kB according to documentation.
https://www.zabbix.com/documentation/2.2/manual/config/items/itemtypes/log_items
In src/zabbix_agent/logfiles.c, zbx_read2():
zabbix_log(LOG_LEVEL_WARNING, "Logfile contains a large record: \"%.64s\""
" (showing only the first 64 characters). Only the first 64 kB"
" will be analyzed, the rest will be ignored while Zabbix agent"
" is running.", value);