Our AEM application is running on 6.5.3. On system overview dashboard, under Sling Jobs, we can see large number of sling jobs either failed or cancelled. Please find below attached image. We need to analyze these jobs in details. Where we can find these sling jobs details? Is there any logs which are specific to these sling jobs?
You can get information about the sling jobs from the following MBEAN: "http://localhost:6530/system/console/jmx/org.apache.sling.healthcheck%3Aname%3DslingJobs%2Ctype%3DHe....
Only the maximum number of queued jobs parameter is configurable and it has the default value of 1000. See  for more details.
The job details are saved in the repository at the location "/var/eventing/jobs".
The link to the OSGI console is "http://localhost:4502/system/console/events". PFB for the screenshot.
The link is present as "Events" under "OSGI" tab under the link "http://localhost:4502/system/console"
There are configuration in the OSGi console where you can even enable history for the "Finished Jobs", by checking the property "Keep History" in the Apache Sling Job Queue Configuration.
If you wish to know why the job failed, then you based on the above analysis, add the logger to the specific job consumer. This way, you will be able to drill down why the job is failing.
The failed sling jobs details would be printed in the error.log file with the stacktrace.You can analyze those.
You can refer consoles - /system/console/slingevent and /system/console/events to view details of these failed sling jobs.