Dumpster 1.0 (Exchange 2007)
- User deletes a message from the "Inbox" or "Sent Items" folder (etc.). The message goes to the "Deleted Items" folder. This is still part of the user's mailbox and counts against their quota.
- User empties the "Deleted Items" folder. The message goes to the "Dumpster". Items in this location apparently do not count against the mailbox quota (more on this below).
- The item remains in the Dumpster for the duration of the retention policy configured for the mailbox database. By default, it is 14 days.
- The Exchange 2007 dumpster is not "searchable" which is a significant disadavantage for mailbox discovery and compliance.
- Users can permanently purge items in the dumpster (if they know where to look). That too represents a disadvantage with respect to mailbox searches and compliance.
In the following sections of this post, I'll refer to different types of deletions. For clarity, let's review the difference between a "soft" delete and a "hard" delete.
Dumpster 2.0 (Exchange 2010)
But just what is a "non-IPM" folder?
A non-IPM folder does not appear in common user interfaces like Outlook and OWA.
It is invisible to the eyes of the end-user.
If "SIR" is not enabled, deleted items simply go to the Deletions subfolder as described above and stay there until removed at the end of the retention period (14 days by default).
So there's no way to right-click and delete that incriminating message!
Questions and answers and more questions.
- Is the dumpster part of the mailbox?
- Do the items in the dumpster count against the users mailbox quota?
- What is the relationship between the cmdlet "Get-MailboxStatistics", the "TotalItemsize" parameter and the "TotalDeletedItemSize" parameter.
Single Item Recovery in Exchange Server 2010
Here's the plan.
I'm going to:
- Delete items
- then delete them from the Deleted Items folder
- and then the dumpster...
I started with this command but the output is not very readable:
[PS] C:\>Get-MailboxStatistics email@example.com | fl *size*
TotalDeletedItemSize : 3 310 038B
TotalItemSize : 115 069 436B
(Yes, I added those spaces).
So let's try this instead:
Let's also consider the size of the mailbox as shown in Outlook:
Note: for some reason, there is a slight difference between 109 MB and 112 MB. However, the resolution of this enigma is outside the scope of this blog post.
1. Delete Items
Now... John Smith deletes 20 MB + of messages in Outlook. What happens to the statistics?
Nothing... no change. Conclusion: the deleted items folder is part of the mailbox AND the items in the deleted items folder are included in the calcuation of "total item size" or total mailbox size. That was expected.
2. Empty Deleted Items folder ("trash")
Now John Smith empties the "Deleted Items" folder. What happens?
The size of the mailbox decreases while the size of the dumpster increases.
Note: "totaldeleteditemsize" measures the size of the dumpster. I'll make some clarifications on this point in my conclusion below.
When I delete items from the Deleted Items folder, the value of "TIS" decreases (87 MB versus 109 MB).
On the other hand, "TDIS" increases (25 MB versus 3 MB).
If "TDIS" was part of "TIS", those numbers would not change, just as they do not change when items are moved from the Inbox or Sent Items to the Deleted Items folder. This seems to confirm that "totaldeleteditemsize" is not included in "totalitemsize".
So... it does appear that although the dumpster is part of the mailbox (as a virtual view of deleted items), the contents of the dumpster do NOT count against the user mailbox quota.
This is what we see in Outlook:
Total size has decreased from 112 MB (in the previous screenshot) to 89 MB.
3. Purge the Dumpster
Now what happens if we empty the dumpster?
John Smith goes to Recover Deleted Items but instead of recovering them, he highlights them all and click on the black X (Purge selected items):
What happens to the mailbox statistics?
So, purging the dumpster in Exchange 2007 affects the TDIS value but not the TIS value.
We can then conclude that "TIS" measures the size of the mailbox, all folders except the dumpster (as it exists in E2K7) and "TDIS" measures the size of the dumpster and the dumpster alone.
In the following lines, I'll reproduce the experiments above but this time with a pair of users on an Exchange 2010 server.
- Items in the dumpster (Exchange 2007 or Exchange 2010) do NOT count against the mailbox quota.
- The "Get-MailboxStatistics" "TotalItemsize" parameter counts all items in the mailbox, deleted items included, but does NOT count items in the dumpster (Recoverable Items folder in Exchange 2010).
- The "TotalDeletedItemSize" counts all the items in the dumpster - and only those items.
Jagott, S. & Stidely, J., et. al. (2010). Microsoft Exchange Server 2010 - Best Practices. Remond, WA: Microsoft Press