Exchange 2016 Transaction Logs for Migration aren’t in Migration Arbitration Mailbox Log Location

exchangeexchange-2010exchange-2016

I've read in a few places that doing a migration with Exchange 2016 should cause all the transaction logs to be located depending on the location of the Migration arbitration mailbox.

I have an Exchange 2010 to Exchange 2016 migration where all the logs are going to the log location defined by the destination mailbox database. What I was expecting was that those logs would instead follow the mailbox database log location that holds the migration arbitration mailbox.

I have E:\EXCH16-MailboxDB1 with log location F:\EXCH16-DB1-Logs.
I also have G:\EXCH16-MigrationMB with log location H:\EXCH16-Migration-Logs.

I recently ran an unfinalized batch migration to move several mailboxes to EXCH16-MailboxDB1. All the logs for migration went to F:\EXCH16-DB1-Logs.

What I'm trying to figure out is why my logs didn't go to H:\EXCH16-Migration-Logs since the migration arbitration mailbox is in G:\EXCH16-MigrationMB and has H:\EXCH16-Migration-Logs configured as the log location.

Best Answer

I spent more time looking into this and I think I found the answer. The behavior I was expecting only applies to migrations involving Exchange 2013 and later. I believe I am seeing the "old" way migrations worked because the source server is Exchange 2010.

https://support.microsoft.com/en-us/help/2800556/large-transaction-logs-are-generated-when-you-move-mailboxes-in-exchan

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Exchange 2010 servers – transaction logs growing faster than expected

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.

Exchange 2010 remove Arbitration mailbox and mailbox store db

The answer according to the OP:

I found the solution:

Get-Mailbox -Arbitration -Database db1 | Remove-Mailbox -Arbitration -RemoveLastArbitrationMailboxAllowed

Best Answer

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Exchange 2010 servers – transaction logs growing faster than expected

Exchange 2010 remove Arbitration mailbox and mailbox store db

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