Does .ost file contain Exchange archive?

I have archiving enabled in Exchange 2010 with 1 year retention for current emails.  For testing, I'm setting up one user who has a total mbox size of 4 gb with Cached Mode enabled.

The result is a .ost size of 4.3 gb which in itself is okay due to Exchange's compression.  However, I was hoping the size would be far less since I assumed the archive would be online and not in the .ost.

In other words:

1 year of current emails = .ost file
Older than 1 year = online archiving

Am I misunderstanding the .ost process?
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Simon Butler (Sembee)ConsultantCommented:
The online archive within Exchange is not cached in the OST file.
Did you archive the content before or after the OST creation? OST files do not shrink on their own, and you do get a lot of bloat in them.

mcnuttlawAuthor Commented:
Yes, the .ost was created after archiving and the option to download shared folders is unchecked (the user has access to other email accounts).

So let's backtrack to Exchange.  When pulling up a user's properties, is the size just for the local (1 year) or is it inclusive of the archive?

Is there a method (GUI or PowerShell) of determining size of the 1 year and archive separately?
Archives are stored in PST files. But the archiving takes time, so if you have just set this up the data will still be on exchange and not yet in the pst. Besides that, once the data is in the pst file that won't automatically shrink the ost file. You'd first have to delete it and allow it to recreate.
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mcnuttlawAuthor Commented:
There's two different answers here.

One says no to the archive and one says yes.
We're both saying the archives aren't stored in ost files. I just said they go to pst files. ost and pst files aren't the same thing.
Simon Butler (Sembee)ConsultantCommented:
PST files are used for archiving within Outlook.
I believe this question is about Exchange online archiving which doesn't use PST files.

The archive is a separate mailbox. Therefore it is counted separately.

The same PowerShell commands as used for mailboxes will get you the archive - you just need to include the -archive parameter:

get-mailbox | get-mailboxstatistics -archive | ft displayname,totalitemsize


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mcnuttlawAuthor Commented:
I amended the command to fit my purpose of querying that one user:

get-mailboxstatistics -identity 'user' -archive | ft displayname,totalitemsize
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