Often Public Folder quotas have been set to a value that is too low or are still set to their defaults. To ensure a smooth migration of your Public Folders, it is necessary to set the quota size to be a higher value. This should be set on both the Source and Destination platforms. The migration will fail unless this is set prior to the actual migration.
These can be set via PowerShell scripts, or through the Exchange Management Console (or Office 365 Admin Portal).
Here is an example PowerShell script that was run against Office 365. The default Office 365 Public Folder quota setting is 2GB, with the issue warning set to 1.7GB. Therefore, this needs to be increased. In this example, we retrieved all the Public Folder settings by using the Get-OrganizationConfig command, and then set the new quota to be Unlimited, and set the issue warning to be set at Unlimited. These can be returned to the values of your choice post migration.
Note: After you apply these settings, wait at least 30 minutes before you start the migration.
$UserCredential = Get-Credential
$Session = New-PSSession -ConfigurationName Microsoft.Exchange -ConnectionUri https://outlook.office365.com/powershell-liveid/ -Credential $UserCredential -Authentication Basic -AllowRedirection
Get-OrganizationConfig | fl *DefaultPublicFolder*
Use the PowerShell script below to set the new quota to Unlimited:
Set-OrganizationConfig -DefaultPublicFolderProhibitPostQuota Unlimited
Use the PowerShell script below to set the issue warning to Unlimited:
Set-OrganizationConfig -DefaultPublicFolderIssueWarningQuota Unlimited
This PowerShell script will need to be run against Office 365, if migrating your Public Folders to Office 365.
Also run a similar PowerShell script against your Source environment in order to set higher quota levels at the Source, prior to the Public Folder migration, or set these via the Exchange Management console.
Follow these instructions to set these via the Exchange Management console:
Use the Limits tab to view or configure storage quotas, deleted item retention, and age limits for the Public Folder.
- Use database quota defaults. Select this checkbox to use the Public Folder database quota limits on which the Public Folder resides. If you clear this checkbox, the Issue warning at (KB), Prohibit post at (KB), and Maximum item size (KB) checkboxes are made available.
- Issue warning at (KB). Select this checkbox to automatically warn Public Folder owners that the Public Folder is approaching its storage limit. To specify this limit, select the checkbox, and then specify the size of the Public Folder in kilobytes (KB) at which you want to prohibit posting. Set the limit to your desired storage maximum, which must be greater than the amount of data to be migrated.
- Prohibit post at (KB). Select this checkbox to prevent posting to the Public Folder after the size of the folder reaches the specified limit. To specify this limit, select the checkbox, and then specify the size of the Public Folder in KB at which you want to prohibit posting. Set the limit to your desired storage maximum, which must be greater than the amount of data to be migrated.
- Maximum item size (KB). Select this checkbox to limit the maximum size of items that users can post to the Public Folder. To specify the size, select the checkbox, and then specify the maximum size of items in KB that users can post to the Public Folders. Enter a value between 0 and 2,097,151KB.
- If there are Public Folders that are larger than 10GB, set the number of licenses to be consumed to a higher value, under Advanced Options. Refer to KB004890 for more information. For example, if the largest Public Folder is 33GB in size, then set this parameter to 4. This will allow up to 40GB of data to be migrated per Public Folder, since each Public Folder license allows up to 10GB of data to be migrated.
- When setting the Advanced Option to a higher value, it will not mean that smaller Public Folder will consume any more licenses when they migrate. For example, a Public Folder that is 7GB in size will only consume one license.
- It is highly recommended that any single public folders at the source be broken down into folders less then 20 GB in size before migrating. Folders larger then that can poorly impact migration speeds and bottleneck a migration from finishing.