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After lurking here for a while I now have a problem I'm hoping you can help with.

We have a pair of Exchange 2010 SP1 servers with two Mailboxes Databases set up as a DAG. Our clients are all using Outlook 2010 on their PCs and about two thirds of our 100 staff have an iPhone 4S.

We noticed recently that the transaction logs are growing far faster than expected - more than 7GB since our last full backup that finished 36 hours ago and we've only sent a small fraction of that volume in mail.

In a typical week we have around 1.5GB of mail in our Journal mailbox, but around 35GB of transaction logs. What is the normal ratio of mail to logs that you would expect to see on a 2010 server as this seems very high to me.

I can see that outside normal office hours we are getting the expected number of logs generated - one every few minutes - but at about 8:30am when staff start work this grows to anything up to a dozen a minute. Exchange User Monitor doesn't show any users that seem to be way above the others in terms of Log Bytes so I'm not sure where they are all coming from. We do have one that's using a lot more CPU time than others but I don't think that's the issue here.

Does anyone have some suggestions where I should go next?

Thanks in advance

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There's no "typical log size" for exchange as this is dependant on activity, not the product itself.

There's an interesting discussion on the microsoft support site here which might be relevant (extract follows).

i had the same issue, and it turned out to be 2 users with android phones in a sync loop on contacts. I basically ran reports showing the top 10 mailboxes by item count (as opposed to size), and was able to narrow it down to the 2 problem users that way (their item count was incrementing very quickly compared to everyone elses. Running the report every 3 minutes let me find the trend

The poster suggested running the following powershell script as their "report"

Get-Mailbox -database databasethatkeepsgrowing | Get-MailboxStatistics | Sort-Object ItemCount -descending |Select-Object DisplayName,ItemCount,@{name="MailboxSize";exp={$_.totalitemsize}} -first 10 | Convertto-Html | out-File c:\temp\report.htm

I reckon you could see this issue from any device that might have problems, including outlook itself if a user or two have messed up OST files or badly behaved plugins - keep in mind that transaction logs aren't just a list of mail but a list of, well, transactions which includes mail but can also include anything that changes the properties of an object in your message store, which can be any number of things. I'd suggest that the high CPU you've noticed could be very relevant, and worth checking out at least.

In addition to that lot, I'd be checking for things like spam relaying and the like, but I'm sure you're all over that.

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