While Running a Backup using EMC Networking on a Vmware Environment you might see the Error Message: “Already exceeding 100 hotadd sessions per vCenter. Reconfigure the sessions accordingly, Total hotadd session count for existing vProxies”
Please note that this Error is not Limited to EMC Network and Could come while Taking Backup from any Backup Solution:
As per the Integration Guide of EMC Networker.
| Component | Maximum limit | Recommended count | Notes | Maximum limit | Recommended count | Notes |
| Number of concurrent hotadd backups per proxy | 25 | 13 | It is recommended to use 13 hotadd sessions to achieve optimal performance. | 25 | 13 | It is recommended to use 13 hotadd sessions to achieve optimal performance. |
| Number of concurrent NBD backups per proxy | 25 | It is recommended to use hotadd transport mode for optimal performance. When using VMware NBD mode, the use of a 10G network is recommended. | 25 | It is recommended to use hotadd transport mode for optimal performance. When using VMware NBD mode, the use of 10G network is recommended. | ||
| Number of concurrent NBD backups per vCenter server | 50 (10G Network) | VMware uses the Network File Copy (NFC) protocol to read VMDK using NBD transport mode. You need one VMware NFC connection for each VMDK file being backed up. The VMware Documentation provides more information on vCenter NFC session connection limits | 50 (10G Network) | VMware uses the Network File Copy (NFC) protocol to read VMDK using NBD transport mode. You need one VMware NFC connection for each VMDK file being backed up. The VMware Documentation provides more information on vCenter NFC session connection limits | ||
| Virtual machines concurrent backups per vCenter server | 100 | 100 | It can be achieved with a combination of the number of proxies multiplied by the number of configured hotadd sessions per vProxy. | 100 | 100 | It can be achieved with a combination of the number of proxies multiplied by the number of configured hotadd sessions per vProxy. |
| Number of proxies per vCenter | 8 | 8 proxies with 12-13 hotadd sessions on each proxy can protect 100 virtual machines concurrently. If more than 8 proxies are required per vCenter, configure the hotadd limits on the proxies to ensure that no more than 100 proxy streams run concurrently against any given vCenter. | 8 | 8 proxies with 12-13 hotadd sessions on each proxy can protect 100 virtual machines concurrently. If more than 8 proxies are required per vCenter, configure the hotadd limits on the proxies to ensure that no more than 100 proxy streams run concurrently against any given vCenter. | ||
| Number of workflows per VMware policy | 64 | 8 | Ensure that you do not exceed 2000 virtual machines per VMware policy. | 64 | 8 | Ensure that you do not exceed 2000 virtual machines per VMware policy. |
| Number of virtual machines per workflow | 2000 | Ensure that you do not exceed 2000 virtual machines per VMware policy. | 2000 | Ensure that you do not exceed 2000 virtual machines per VMware policy. Note that the maximum of 2000 virtual machines per workflow is only applicable to the first FULL backup to Data Domain, and does not apply to CBT-based incremental backups of the virtual machines. However, ensure that you do not exceed 100 connections per vCenter at any time during the backup window. |
So as per the above Table. You can have 8 Proxies and each of these Proxies can handle 12-13 VMs, which makes the No. 100.
It is recommended Not to exceed this value as it might cause issues with the Backup Application as well as the vCenter.
