EMS basics in Visual C#.NET

Maker Quick Response Code in Visual C#.NET EMS basics

Even though we ask the server-side filter to do more work (working with any reasonably sized set of mailboxes, the server-side filter will have to process significantly more data to find the first 5,000 mailboxes that match), it still executes faster. For example, when I executed similar commands within a very large Exchange organization (170,000 mailboxes), the server-side filter completed processing in 43 seconds, whereas the client-side filter completed in 81 seconds. The rule here is that the effect of server-side filtering gets better and better as the number of objects increases.

Another aspect to consider is that PowerShell does not have the ability to fetch and cache data on disk temporarily in the way that a database might . This is not an issue if you want to process only a few objects, but it can lead to memory issues if you attempt to process tens of thousands of mailboxes at one time, especially if you use client-side filters and want to pipeline the output to another command . In this case, you ask owerShell to find all the objects that match the specified filter, store the data P in memory, process the data, and pipe the matching objects to the second command . Experience shows that these operations can cause PowerShell to complain that it is running out of memory . This is likely to be one of the growing pains that all software goes through and apart from using loops to process data there is not a good solution to the memory exhaustion problem available today .

Sometimes people make the mistake of assuming that the client-side filter is faster because server-side filters provide the data in one motion after the server processes all the data. You therefore wait for a while without seeing anything and then see all the filtered records at one time. By comparison, the client-side filter fetches and filters data continuously and so you see output as the command finds each matching record. However, the important indicator of performance is how long each type of filter takes to complete and server-side filters are always faster. The commands that you are most likely to use with server-side filters are as follows:

Get-User Retrieve basic Active Directory properties for any user account, including mail-enabled accounts. Get-Mailbox Retrieve Exchange-specific properties for mailboxes. Retrieve Exchange-specific properties for mail-enabled contacts. Retrieve Exchange-specific properties for mail-enabled

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Each of the commands that you can use to work with user accounts, groups, and mailboxes supports a different set of filterable properties. To discover what properties are available for filtering, you can use PowerShell to query the properties of a returned object. For example:

Get-Mailbox -Identity Redmond | Get-Member | Where-Object {$_.MemberType eq 'Property'} | Sort-Object Name | Format-Table Name

This set of commands calls a command to return some information about an object. It then pipes the information returned by the first command to the Get-Member cmdlet, which extracts information about the properties. We sort the properties by name and output them in table format. The output looks like this:

Name ---AcceptMessagesOnlyFrom AcceptMessagesOnlyFromDLMembers AddressListMembership Alias AntispamBypassEnabled CustomAttribute1 CustomAttribute10 CustomAttribute11 CustomAttribute12 CustomAttribute13 CustomAttribute14 ... WindowsEmailAddress

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This method works for the Get-Mailbox, Get-CASMailbox, Get-User, Get-Recipient, GetDistributionGroup, and Get-DynamicDistributionGroup cmdlets. You can use any of the values reported in a Filter statement. For instance, the call that we just made to Get-Mailbox reports that the custom attributes are available, so to find all mailboxes that have a value in the CustomAttribute10 property, we can generate a command like this:

Get-Mailbox Filter {CustomAttribute10 ne $Null}

If you look at the filterable properties reported by the Get-DynamicDistributionGroup cmdlet, you can see that the ManagedBy property is available for this dynamic distribution group, whereas it is not for mailboxes. Hence, we can execute a filter like this:

Get-DynamicDistributionGroup Filter {ManagedBy ne $Null}

When you create a filter, it is best to be specific as possible. You can state several conditions within a filter. Another example of a server-side filter that returns all the mailboxes in the Dublin office where the user name contains Tony is shown next. The Get-User cmdlet also