How to monitor Marketo Sync?

I just look at the last sync in the integration area in admin to make sure it is syncing, as well as looking at notifications of any sync errors that occur in the notifications area at the top of my user interface in Marketo.

You can use supportTools to get some basic stats on if it's working or if there is a syncClog (unofficial term)

app-###.marketo.com/supportTools/sfdcSyncStats 

^ change for your instance  

UPDATE:  
With recent changes to the front end, it might not be apparent what your app-id is.  These days, it's easiest to pull up a person record and get it from there.

For example: app-mk01.marketo.com/leadDatabase/loadLeadDetail?leadId=1234567

Will have a supportTools link of: 
app-mk01.marketo.com/supportTools/sfdcSyncStats 

You have several options. It helps to check the "Notifications" section in Marketo as sync issues (among others) will often appear there. You can also put together a smart list to check for folks who failed to sync (there are probably a few ways to assemble the criteria to do this) that way you'll have a bucket already assembled of the records that didn't make it over to SFDC. The downside here is you have to remember to check the lists every so often. 

Hi Suman,

You definitely should go to "Notifications" and subscribe for specific Notification Types like 'CRM sync' in your case.

Marketo will send email to you, if something goes wrong.

This is not very 'Real-time', as these notification emails will be sent once a day. Better than nothing.

You can also create custom notifications via smart campaigns. This will work for the first push to SFDC.

Let's say you have the smart campaign for pushing leads to SF.

Just add 'Wait' step for couple of minutes, and then 'Send Alert' with the condition: If SFDC Type is empty - send alert to your email address.

This will provide you with almost real-time information.

There is also the downside here: if you have batch of failed leads, you will receive notification for every one of them.

Another solution is to create people performance report based on some criteria and subscribe for it on daily basis.

If you don't have any exotic custom criteria, then general notifications will do the work and you don't need the report.

Again, you will receive email once a day.

You will receive it even if everything goes well, you will just see 'People failed: 0'. To make it more useful, you can add more interesting statistics in your report.

Compared to the smart campaign alert approach, you will receive only 1 message in case of 1000 failed leads.

I hope this helps.

Atomatest will make sure all your sync scenarios are working - in case it a clog in just a couple of syncing campaigns.  https://launchpoint.marketo.com/automaton/automaton-automated-operations-and-configuration-testing-and-monitoring

There's no way that I know of to get all sync errors in realtime, which is unfortunate. I make it part of my daily routine to check the Notifications tab first thing. You can also set up email alerts for critical issues. I also have a running spreadsheet of errors and if there is anything that I see coming up consistently I can flag it and try to pin down the root cause.