Exchange Online Migration: Deprecation of BadItemLimit and use of Data Consistency Score
Hi All,
If you are a frequent Reader of the Exchange Team Blog, then you probably saw, that they announced to depreciate Bad Item Limit (BIL) and Large Item Limit (LIL) until end of 2022.
Deprecating bad item limit and large item limit migration parameters
https://techcommunity.microsoft.com/t5/exchange-team-blog/deprecating-bad-item-limit-and-large-item-limit-migration/ba-p/3652478
Migrations with Data Consistency Score (DCS) – more than you ever wanted to know!
https://techcommunity.microsoft.com/t5/exchange-team-blog/migrations-with-data-consistency-score-dcs-more-than-you-ever/ba-p/2393406
https://techcommunity.microsoft.com/t5/exchange-team-blog/deprecating-bad-item-limit-and-large-item-limit-migration/ba-p/3652478
Migrations with Data Consistency Score (DCS) – more than you ever wanted to know!
https://techcommunity.microsoft.com/t5/exchange-team-blog/migrations-with-data-consistency-score-dcs-more-than-you-ever/ba-p/2393406
Let's see that in Action
Connect-ExchangeOnline
$ONPREMCREDS = get-credential "CORP\Administrator"
Let's create a MoveRequest with the BadItemLimit Parameter. You see there is a warning.
$Mailbox = "demo02@icewolf.ch"
New-MoveRequest -Identity $Mailbox -Remote -RemoteHostName mail.icewolf.ch -TargetDeliveryDomain icewolfch.mail.onmicrosoft.com -RemoteCredential $ONPREMCREDS -BadItemLimit 100
New-MoveRequest -Identity $Mailbox -Remote -RemoteHostName mail.icewolf.ch -TargetDeliveryDomain icewolfch.mail.onmicrosoft.com -RemoteCredential $ONPREMCREDS -BadItemLimit 100
With the MoveRequestStatistics you can see that the DataConsistencyScore is not used
Get-MoveRequest -Identity Demo02@icewolf.ch | Get-MoveRequestStatistics | ft DisplayName, Status, StatusDetail, DataConsistensyScore, BadItemsEncountered, PercentComplete
New MoveRequest without the BadItemLimit or LargeItemLimit Parameter
$Mailbox = "demo04@icewolf.ch"
New-MoveRequest -Identity $Mailbox -Remote -RemoteHostName mail.icewolf.ch -TargetDeliveryDomain icewolfch.mail.onmicrosoft.com -RemoteCredential $ONPREMCREDS -BadItemLimit 100
New-MoveRequest -Identity $Mailbox -Remote -RemoteHostName mail.icewolf.ch -TargetDeliveryDomain icewolfch.mail.onmicrosoft.com -RemoteCredential $ONPREMCREDS -BadItemLimit 100
Now the DataConsistencyScore is used
Get-MoveRequest -Identity Demo02@icewolf.ch | Get-MoveRequestStatistics | ft DisplayName, Status, StatusDetail, DataConsistensyScore, BadItemsEncountered, PercentComplete
DataConsistensyScore is "Perfect"
Let's make some trouble:
I've added MAPI Permissions with the Icewolf.Exchange.MAPI Module for demo06@icewolf.ch. And then i deleted the demo06 Account and waited until AAD connect has deleted the Account also in ExchangeOnline.
Add-MAPIPermission -Mailbox demo05@icewolf.ch -Trustee demo06@icewolf.ch -AccessRight Reviewer -Folder Inbox -I
ncludeSubfolders $true
ncludeSubfolders $true
Let's create another MoveRequest to ExchangeOnline
$ONPREMCREDS = get-credential "CORP\Administrator"
$Mailbox = "demo05@icewolf.ch"
New-MoveRequest -Identity $Mailbox -Remote -RemoteHostName mail.icewolf.ch -TargetDeliveryDomain icewolfch.mail.onmicrosoft.com -RemoteCredential $ONPREMCREDS
New-MoveRequest -Identity $Mailbox -Remote -RemoteHostName mail.icewolf.ch -TargetDeliveryDomain icewolfch.mail.onmicrosoft.com -RemoteCredential $ONPREMCREDS
As you can see the DataConsistensyScore is not "Perfect" but "Good"
Get-MoveRequest -Identity Demo05@icewolf.ch | Get-MoveRequestStatistics | ft DisplayName, Status, StatusDetail, DataConsistensyScore, BadItemsLimit, BadItemsEncountered, PercentComplete
Let's find out what caused the DataConsistencyScore to change. It's the seven Folders with MAPI Permissions where the User was deleted.
$MRS = Get-MoveRequestStatistics demo05@icewolf.ch -IncludeReport -DiagnosticInfo Verbose
$MRS.Report.Failures | group FailureType | fl
$MRS.report.Failures | foreach { $_ | Select-Object @{name="index";expression={$i}},timestamp,failurecode,failuretype,failureside;$i++} | ft
$MRS.Report.Failures | group FailureType | fl
$MRS.report.Failures | foreach { $_ | Select-Object @{name="index";expression={$i}},timestamp,failurecode,failuretype,failureside;$i++} | ft
If you need to Investigate and check - that's the way to go.
As long the Mailbox has not completed you can always remove the Move Request (Remove-MoveRequest)
Often helps to Move the Mailbox in the Source to another Mailbox Database.
If that does not help try New-MailboxRepairRequest
If you find the Data Loss is Acceptable you can do that with the following Command (Sorry i was not able to create enough trouble to create a Screenshot)
Set-MoveRequest -Identity Demo05@icewolf.ch -SkippedItemApprovalTime $([DateTime]::UtcNow)
Set-MoveRequest -Identity Demo05@icewolf.ch | Resume-MoveRequest
Wish you all the best for your Exchange Migrations!
Regards
Andres Bohren
