So typically you have the following
1. Provisioning set to run twice per day, for example, 7am and 7pm
2. Mailbox Synchronization to run twice per day, for example 8am and 8pm
3. Archiving Task scheduled tor run from 10pm to 3am
4. Backups scheduled to run from 3am to 7am
That way no process steps on each other
The provisioning runs at 7am, synchronizes AD and Exchange changes to any mailbox, along with any changes you have made in your provisioning groups, it then adds the user or updates the existing user in the EV Directory database
Then at 8am, provisioning should have completed, Synchronization then takes place
It connects to each mailbox and updates the EV Hidden Message , with all the settings of the Desktop and Mailbox Archiving policies, which may have been updated by a user changing a policy setting, or maybe the user has switched provisioning groups, they now have to be sync'd to have the correct archiving policies set
So when archiving takes place, it does the following
1. Connects to the mailbox and reads the hidden message
2. It determines settings like, should it create a shortcut, should it archive items that are unread? how old should a mail item be before its archived? should it archive large large messages first etc
3. It then scans each message in each folder and sorts it in to a list. For instance if you have the checkbox "Start with items larger than".... it will sort that list in to largest to smallest and start archiving through the top of the list to the bottom
4. After it has archived the maximum messages per pass, it will then go on to the next mailbox
The messages per pass are configured in the Task properties for the exchange server
by default it's set to 1000 messages per pass... meaning the maximum it will archive at one time is 1000 messages, if there are more messages still to archive, if it finishes archiving all the other mailboxes, it will come back to that mailbox and archive another 1000 messages
The reason for this, is you may have a number of huge mailboxes, and the archiving run spends all its time on a few mailboxes, and archives nothing in any of the other mailboxes because it just ran out of time
As for the Quota based archiving, here is a good overview of Quota based archiving
https://www-secure.symantec.com/connect/blogs/quota-based-archiving-how-it-works-and-why-you-may-wrongly-believe-it-does-not