Storage has come a long way from the days when disk space was selling for $700,000 a gigabyte, but that doesn’t mean you can ignore storage quotas for in your Exchange infrastructure.
No matter what the size of a mailbox is, there will always be some users who will exceed it unless you keep a leash on them. You can do that through storage quotas.
Storage quotas are size limits you can impose on your users’ mailboxes. They can be configured through the Exchange Management Console or Shell and the properties option for the database for a group of mailboxes.
Ordinarily, you’d want to set a quota for an entire mailbox database, but you can set a quota for individual mailboxes, too. That can only be done through the Console or shell, though, and it will override the quotas set at the database level.
You can access the properties to a database through the Console. On the Console tree, you navigate to Organization Configuration > Mailbox. In the result pane that appears, select a database to configure from the Database Management tab.
Under the database name, an action pane will appear. Click Properties to display a series of tabs for configuring the database. The Limits tab is used to set quota levels.
You can set up to three quotas for a mailbox. Each triggers a warning or a warning and an action when a user exceeds the quota.
For example, let’s say your maximum mailbox size is 2GB. You may want to set your first quota at 1700MB. (The form fields on the limits screen are calibrated for megabytes.) That means when a user’s email storage exceeds 1.7GB, they will receive a warning, “Your mailbox is almost full” and the advice “Please reduce your mailbox size. Delete any items you don’t need from your mailbox and empty your Deleted Items.”
A second quota could be set at 1800MB. By default, that warning will prohibit the user from sending any more mail until they clean up their act. If you set a second quota, you must make sure your first quota is greater than 50 percent of it, otherwise the first warning won’t be triggered.
Finally, you may want to set a third quota at 1900MB. Along with warning a user that their mailbox is about to max out, breaking this quota will cut off both sending and receiving mail by the user.
You don’t have to set all three quota levels. You may want to set up the first quota, for instance. If you do that, however, the user will receive a message that says, “Your mailbox is becoming too large. The current size is xxMB.” With all quotas enabled, the warning messages contain a bar graph that shows used and unused mailbox space.
A number of other options are available from the Limits tab, too. For example, you can set the interval at which mailboxes are scanned for compliance with the quotas or set the number of days a mailbox may retain deleted messages.
By setting quotas for your users’ mailboxes, you head off future problems, such as filling up the disk space in the partition that’s home for your mailbox database.