Exchange ActiveSync (EAS) with large mailbox folders

[guest]

I have always had issues syncing a large folder with EAS. This has been a problem with any phone that I have setup with EAS. The problem is not that it will not sync, but rather if the EAS settings are set to "As Items Arrive", the email items don't actually get delivered until the next heartbeat interval (approx. 15 minutes).

EAS is setup for delivery "as items arrive" and to sync the "last 2 weeks". In my case, I keep my inbox quite clean (less than 200 items) and that works fine. However, I'd love to have my sent items to sync as well (more on that in a second). If I select my sent items folder to sync (which has about 35000 messages in it) - emails no longer arrive in the short timeframe as per usual (usually within 60 seconds). Instead, it takes until the next heartbeat interval of approximately 15 minutes. Effectively, this makes the "as items arrive" setting useless and I might as well set it to check every 15 minutes (not desireable).

I have always dealt with this thinking there must be a limitation of EAS and large folders. My guess is that because there are so many items in the folder it just can't manage the state of them in a timely manner. However, I would have thought the programmers would have set it to only watch the last 2 weeks of messages (or however you have your sync settings configured).

I bring this issue up now because I've just updated my WP7 phone to Mango. I noticed today that my emails were being delayed. Upon further investigation, I noticed that the new default conversation view re-enables the sync of the Sent Items folder (obviously so the email thread looks nice in the conversation view). This was the cause for my 15 minute email delays and as soon as I disabled the sent items folder sync, the delivery timeframe went back to normal. Note - the conversation view doesn't depend on the sent items sync but without that part, the conversation view is one-sided.

We are running Exchange 2003 with all of the latest updates. I have tested this over the years with many devices on many different Exchange 2003 servers (sadly, nothing newer yet) and all of them have the same issue with large folders. I am using the Sent Items folder as an example but the same is true for any large folder. So, my long-winded questions are - does EAS have a real issue syncing large folders with the "as items arrive" setting? Is this only present in Exchange 2003 or is it also present in 2007 and 2010? Are there any workarounds?

I am quite surprised that I haven't been able to find much info re: this online. I can't be the only one that has a large sent items folder?

[guest]

Based on my further research, this issue is most likely occur on Exchange environment. So, I suggest you install below two HOTFIX:



The W3wp.exe process uses almost 100 percent of CPU resources when you synchronize large e-mail messages in Exchange 2003 Service Pack 2

http://support.microsoft.com/kb/941439/en-us



The worker process for Exchange ActiveSync crashes when end-users try to synchronize their third-party devices with an Exchange Server 2003 server

http://support.microsoft.com/kb/957191/en-us



Meanwhile, I suggest you modify the below registry key:



Key: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\MasSync\Parameters

Value: MaxAllocationIncrement

Type: REG_DWORD



Added the value: 524288 (Decimal)



Then, please run "IISRESET" to restart IIS and monitor the issue.



Also, as this seems to be a known issue on Exchange 2003, the best way to workaround this issue is to archive the items in Sent Items folder to PST.