Here is the current content from MS. It is currently unpublished and could change they said.
Symptoms Consider the following scenario: * You have a mixed Microsoft Exchange Server 2010 and Microsoft Exchange Server 2003 environment. * You use an Exchange Server 2010 Client Access server to proxy requests for Exchange Server 2003 mailbox servers. * Users try to access the mailboxes that are hosted on Exchange Server 2003 servers by using IMAP4 clients. * The Exchange Server 2010 Client Access server is under heavy load. In this scenario, the Microsoft Exchange IMAP4 service on the Exchange Server 2010 Client Access server may stop responding. Therefore, the IMAP4 clients cannot connect to the mailboxes. Cause This issue occurs because of a deadlock situation, which is caused by a timing issue when the sessions are managed and released. Additionally, issues in network performance may cause this issue to occur more frequently. Resolution To resolve this issue, install the following update rollup: 2492690<http://vkbexternal.partners.extranet.microsoft.com/VKBWebService/ViewContent.aspx?scid=KB;EN-US;2492690> Description of Update Rollup 3 for Exchange Server 2010 Service Pack 1 Workaround To work around this issue, you have to restart the Microsoft Exchange IMAP4 service on the Exchange Server 2010 Client Access server. Status Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section. From: Young, Darren [mailto:darren.yo...@chicagobooth.edu] Sent: Friday, March 04, 2011 8:02 AM To: MS-Exchange Admin Issues Subject: IMAP Issue Opened a case with MS and were told yesterday that the IMAP issue we have been experiencing is known and they have an interim update for it. KB on the file is 2496083 but I am unable to find any public reference for that anywhere. I asked the engineer for details. >From them: "My name is XXXXX and I'm an Escalation Engineer on the Exchange team at Microsoft. I just looked through the dumps and iDNA traces for your IMAP issue, and it looks like you're running into a known bug that causes a thread deadlock in the IMAP process. This bug is scheduled to be fixed in Exchange 2010 SP1 RU3. I don't have a release date on that, but it should be out fairly soon. In the meantime, we can give you an Interim Update which will fix this specific issue. We currently already have an Interim Update built for SP1 RU1 and SP1 RU2, but don't have one for straight SP1. I wanted to see if you are interested in getting an Interim Update, and if so, if you would like one of the ones already built for RU1 or RU2? If you want one for straight SP1, we can build that too, but it will probably take 3-5 days to build." The problem is fairly reproducible, when the Imap4.exe process reaches around 1.1-1.2GB working set it stops processing client requests. It never hangs or dies, it just ceases operating. Darren Young Systems & Security Architect Computing Services University of Chicago Booth School of Business 5807 South Woodlawn Avenue Chicago, IL 60637 Voice 773.702.0331 | Fax 773.702.0233 --- To manage subscriptions click here: http://lyris.sunbelt-software.com/read/my_forums/ or send an email to listmana...@lyris.sunbeltsoftware.com<mailto:listmana...@lyris.sunbeltsoftware.com> with the body: unsubscribe exchangelist --- To manage subscriptions click here: http://lyris.sunbelt-software.com/read/my_forums/ or send an email to listmana...@lyris.sunbeltsoftware.com with the body: unsubscribe exchangelist
