Here is a common archiving/eDiscovery/compliance FAQ I put together based several education customer discussions:
If I currently have a 3rd party on-premises archiving solution does Exchange in-place archiving in Office 365 do the same thing?
No, it is not an exact match of functionality since we have more granular capabilities in Exchange Online where we break out archival of email (Exchange In-Place Archiving) from the preservation of email (Exchange In-Place Hold).
As you can imagine because we are more granular in capabilities, this is the an area which leads to quite a bit of confusion for everyone since there are multiple definitions of Exchange “archiving”. These two capabilities can be complementary or separate if need be where in a lot of on premises Exchange archiving solutions they are one in the same.
Exchange Online’s In-Place archiving is separate ‘mailbox’ for storing older email to be archived. The best analogy about Exchange In-Place Archiving is this is a server side/cloud based PST. You can delete mail from your PST on premises and the same is true for Exchange in-place archiving.
In-Place Archive mailbox end user OWA view
If the your goal is to achieve PRESERVATION of email (e.g. 3 year retention) which is what 99.9% of customers are looking for when replacing their older 3rd party Exchange archiving solution than the only way to accomplish this is with Exchange In Place Hold. This will preserve content in both primary mailbox and in-place Archive mailbox as well as Lync conversations.
Administrator view of enabling In-Place Hold on a mailbox. PowerShell can also be used for bulk enablement.
What components do I get with add-on Exchange Online Archiving SKU with Office 365?
You get two features with the EOA add-on SKU for Office 365:
You can also get this functionality with the Exchange Plan 2 license as well as the A3 license. See here and here for more info on licensing options.
Are my Exchange Online unlimited in-place archives tamper proof and preserved by default?
Not by default. Unlimited Exchange In-place Archives mean the archive mailbox is unlimited in size (100 GB default but can be increased to a larger size via escalation) and unlimited in retention duration. If a retention policy is created to archive mail every 180 days, for example, mail is moved from the primary mailbox to the archive mailbox however it is NOT preserved and mail can be altered in those archives. Any mail in the in place archive can be found using in place eDiscovery and also can be found in the Outlook 2010+ or OWA browser as well. This allows for easy discoverability and clean end user access to their archived email.
To preserve and prevent tampering of these In-place Archives in the In-Place Archive mailbox or mail which is in the primary mailbox, you must enable Exchange In-Place hold on the mailboxes in question. This will log any alterations and preserve any emails deleted from the primary or archive mailbox.
How many eDiscovery types are in Office 365? What licenses do I need for it or them?
Two types. Exchange In-Place eDiscovery using Exchange Administration Console and eDiscovery Center as part of SharePoint Online. Exchange in place eDiscovery is included with the A2 license for both admin console and for searches and SharePoint eDiscovery Center requires A3 license for both admin queries and for the users which are searched.
Exchange In-Place eDiscovery console more on this here
SharePoint eDiscovery Center – more on this here
Are there any limits on eDiscovery search size in Exchange Online? If yes, how do you get around it?
Yes, Exchange in-place eDiscovery is capped at 5,000 mailboxes for search size using the EAC GUI. We designed this to be for smaller searches on average we found most customers search no more than 20 mailboxes at a time. If a customer wants more than 5000 they must use PowerShell to query larger mailbox sets. See here for search-mailbox options.
SharePoint eDiscovery search also has limits of 100 SharePoint sources, 1500 exchange sources, and 500 keywords.
What are the four “in-place” compliance/retention features in Office 365? What licenses do I need for each? What does each one do?
I put together a matrix to help with this:
Where can I learn more details on these topics discussed abofe?
This is a great starting site here. It has very useful videos walking through the Exchange In-Place components discussed above.
See here and here for more details on archiving and retention.
More on SharePoint In-Place Hold and eDiscovery see here.
Best reference I have seen for limits and licensing on eDiscovery is here.