Our SFDC team loaded about 200k records wrongly (I know..) in the past week and those got syned over to Marketo. Few days later, they deleted those then uploaded again. We found out that when these wrong data were deleted from SFDC, those still stay in Marketo. For the reason, now we have about 200k duplicate records.
Here are my questions:
I’ve generated a smart list to locate the leads that have been created from SFDC and deleted lately. How can I double verify and make sure if they’re safe to be removed? I think they're safe to delete but want to play it safe.
Is there a way to prevent this happened again? Can SFDC/Marketo stop these new contacts/leads synced over to Marketo till SFDC team feel like the data load is good and ready?
There are definitely some ways to ensure you delete the appropriate records. I'd try pulling a smart list with the following filters:
There are likely some additional filters that are specific to your instance that you may also want to apply, but this should help get you started in identifying the SFDC deleted records. However, before doing any sort of deleting in Marketo, I'd open a Marketo Support case and work with them to ensure you're removing the appropriate records. They may have some backend tools that could identify the records for deletion and give some recommendations for deletion - ie: in batches or during off-hours. Good luck!
Re: "Can SFDC/Marketo stop these new contacts/leads synced over to Marketo till SFDC team feel like the data load is good and ready?"
You can create a custom sync filter with Marketo's help that will prevent Leads/Contact from syncing to Marketo if it's checked (e.g., "Do Not Sync to Marketo") - and then make sure your SFDC team includes that column (set to True) for any large list imports. Then have them set it to False when the people are ready to sync over.