Saturday, October 28, 2017

Continued protection with VM migration

VM migration refers to the process in which a running VM moves to another physical machine, keeping memory, network connectivity, and storage intact, which implies the application continues to run as-is without any disruption. This can happen due to a host server crash or due to re-balancing the resources in a cluster. So the expectation is that backups should run uninterrupted even if the VM moves to another node in the same cluster or even a different cluster. The same DPM server continues to protect the VM even after live migration. If the VM moves to a different cluster, DPM integration with Virtual Machine Manager helps discover the VM on a node in the new cluster.

Protecting replica VMs
The first question that comes to customers’ minds is whether they should protect the replica VMs. In customer conversations, three scenarios are found to be useful when protecting replica VMs:

 Reduce the impact of backup on the production workloads In today’s world, workloads need to run 24 hours a day, 7 days a week with high performance. Workloads run on differencing disks during the backup operation and do impact the system.

Limited network bandwidth between the branch office and head officeNetwork bandwidth is expensive, and it is redundant to send data to the head officetwice, once for disaster recovery and then for backup. A more efficient way is tosupport backup from a replica site so that customers can manage the backupinfrastructure from a single site.

Enterprise to hoster scenario Most customers don’t want to build anotherdatacenter for disaster recovery and prefer to leverage a hosting service provider orpublic cloud. Hosting service providers offer SLAs around backing up customers’ VMson a regular frequency (for example, daily), and this can be easily achieved usingreplica VM backup.

There is some limitation with these scenarios: you can only get crash-consistent backups. However, most customers are comfortable with this. Remember, crash-consistency doesn’t mean inconsistency. It’s equivalent to the state when the power plug is pulled. Applications know how to recover from this state.

Protecting servers in workgroups and untrusted domains
DPM supports protecting Hyper-V VMs on the servers that use local user account (NTLM authentication) or that use certificates. For Hyper-V clusters, only certificate authentication is supported, not the NTLM certification. Even protection of a primary DPM server to a secondary DPM (in an untrusted domain) is supported through certificate authentication.

Source of Information : Microsoft System Center

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