java.lang.OutOfMemoryError: GC overhead limit exceeded
Symptoms:
On a (multi) project snapshot with issues creation Configuration Manager fails with an error similar to this.
Cause:
This can happen in case the system contains issue data that is disproportionate to the amount of system memory / heap size allocated on the environment. Refer to Atlassian's Jira sizing guide  https://confluence.atlassian.com/enterprise/jira-sizing-guide-461504623.htmlÂ
Note that creating a very large snapshot (e.g. of projects with tens of thousands of issues) may also require additional memory to be allocated for the heap.
Resolution:
Refer to the following article and more specifically to increasing JIRA application memory for instructions how to resolve this issue.