There is a periodically (once a few minutes) error message in the zabbix logs:

19155:20120703:220000.143 [Z3005] query failed: [1213] Deadlock found when trying to get lock; try restarting transaction [update items set name='disk: drbd101 iops',key_='disk.iops[drbd101]',type=15,value_type=3,data_type=0,delay=60,delay_flex='',history=3,trends=365,trapper_hosts='',units='iops',multiplier=0,delta=0,formula='1',logtimefmt='',valuemapid=null,params='last("disk[reads,drbd101]")+last("disk[writes,drbd101]")',ipmi_sensor='',snmp_community='',snmp_oid='',port='',snmpv3_securityname='',snmpv3_securitylevel=0,snmpv3_authpassphrase='',snmpv3_privpassphrase='',authtype=0,username='',password='',publickey='',privatekey='',description='',interfaceid=null,flags=4 where itemid=346477;
update item_discovery set key_='disk.iops[

]',lastcheck=1341345599,ts_delete=0 where itemid=346477 and parent_itemid=344945;
[...]

Full error message in deadlock.log attached file.

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