Our Exchange 2010 servers are virtualized with VMWare ESX 4.1. We have two mailbox servers in a DAG with five databases. This afternoon we were forced to do a firmware update on our SAN to address a potential serious issue. For the update I put one of our mailbox servers in maintenance mode and turned it off (just in case). During the update there was an approximately 20 second period of very high storage I/O latency. The mailbox server which was still up threw several 507 and 508 errors about the extremely high latency to read and write. It then threw up 8 event 531 warnings (see below). Since I know my storage isn't failing or having errors, are these something I can safely ignore? All the databases are replicating, and show as healthy. All the indexes show as healthy as well. Log Name: Application Source: ESE Date: 5/11/2012 4:58:58 PM Event ID: 531 Task Category: Database Corruption Level: Warning Keywords: Classic User: N/A Computer: Exchange2.HQ.Donohoe Description: Information Store (2700) The database engine attempted a clean write operation on page 2581807 of database D:\DCC\DCC.edb. This acton was performed in an attempt to correct a previous problem reading from the page. For more information, click http://www.microsoft.com/contentredirect.asp. Event Xml: <Event xmlns="http://schemas.microsoft.com/win/2004/08/events/event"> <System> <Provider Name="ESE" /> <EventID Qualifiers="0">531</EventID> <Level>3</Level> <Task>12</Task> <Keywords>0x80000000000000</Keywords> <TimeCreated SystemTime="2012-05-11T20:58:58.000000000Z" /> <EventRecordID>64952</EventRecordID> <Channel>Application</Channel> <Computer>Exchange2.HQ.Donohoe</Computer> <Security /> </System> <EventData> <Data>Information Store</Data> <Data>2700</Data> <Data> </Data> <Data>2581807</Data> <Data>D:\DCC\DCC.edb</Data> </EventData> </Event>

Still getting errors in the event logs? If no, you are probably ok and dont need to do anything. If you see more, re-seed that mailbox store from another copy

No more errors or warnings in the event log. They only happened during the 10-20 seconds where the SAN had high latency during its firmware update. Everything has been fine since; no more errors, no more warnings.

Hi Zoltank If the problem is solved, please Mark As Answer and Finish this thread CheersZi Feng TechNet Community Support