Content Libraries syncing is very slow between vCenters

Products

• VMware vCenter Server 8.0

Issue/Introduction

• When attempting to publish an entire Content Library containing multiple VM templates to a subscribed Content Library, the publish operation is successfully queued as a task but fails to progress. The task remains in a "queued" state indefinitely and does not complete or report any errors.
• Publishing task gets stuck at 0% and does not allow new deployments to happen
• The following command will display content library tasks stuck in queue state:
  
  /opt/vmware/vpostgres/current/bin/psql -U postgres VCDB -c "select * from cl_simple_activity;"

Cause

Each publish operation within the Content Library is handled as an individual thread. By default, the system allocates a maximum of 24 concurrent threads for these operations. If the number of requested publish actions exceeds this thread limit, the system may enter a stalled state. In such cases, the operation remains queued indefinitely, waiting for available threads that never free up—effectively causing the process to hang. This behavior is typically observed when attempting to publish a large number of VM templates simultaneously, exceeding the thread capacity of the Content Library service.

Resolution

Increase the threadPool for the Content Library service.

1. Take a snapshot of vCenter
   
   
2. Backup the configuration file
   
   cp /etc/vmware-content-library/vdc.properties /root/vdc.properties
   
   
3. Appending the following line to the bottom of /etc/vmware-content-library/vdc.properties (note the number 60 may need to change depending on the size of the content library operations being requested. It could be larger or smaller.)
   
   echo "cls.activity.threadPool.size=60" >> /etc/vmware-content-library/vdc.properties


4. Restart content library service
   
   service-control --restart vmware-content-library