Home‎ > ‎

Number of concurrent API sessions with vSphere 6.0 and 6.5

I went through few blogs which claimed that maximum number of concurrent API sessions are 500 and we have to change it. It was true for versions before 5.0, but not anymore.

All backup vendors that use VMware VADP implement the VMware VDDK kit in their solutions. This kit provides standard API calls for the backup vendor, and helps to read and write data. During backup operations, all vendors have to deal with two types of connections: the VDDK connections to vCenter Server and ESXi, and vendor’s own connections. The number of VDDK connections may vary for different VDDK versions

If you try to back up thousands of VMs in a very short time frame, you can run into the SOAP session count limitation. 

vCenter now allows up to 2000 concurrent sessions. This 2000 can be comprised of API, UI, Remote Console, etc.

vCenter can support up to ~600 concurrent operations before it begins to queue them. So you might see some operations get queued temporarily if you try to do 600 things at exactly the same time.