Why GC takes too long time to finish in AEM6.3

Statement: Why GC takes too long time to finish
Solution:
Possible Reasons

• Large repository size – GC performance proportional to repository/datastore size
• DataStore GC executed for the first time or after a long gap

Identification

• GC has info level logs for each phase and it is easy to identify the phase taking the longest time.
• Empirically, deletions could take the maximum time even spilling over 24 hours if large number of blobs to be deleted

Mitigation

Regular DataStore GC
o Mark phase (collection of blob references used) can affect general repository performance critically so, should be scheduled during off-peak hours
o Sweep phase should not critically affect system performance so, Ok to have it continue if it spills over to normal working hours