Vmotion without VPLEX
- Cannot directly perform Vmotion since storage is not shared
- Must first perform storage Vmotion
Vmotion with VPLEX
- Enables direct Vmotion between data centers
- Storage Vmotion is no longer required
- Replicate the data once then move the VMs at will
Use Cases
- Data Center Load Balancing
- Optimize resources across several data centers
- Disaster Avoidance and Data Center Maintenance
- Evacuate data center ahead of a probable disaster
- Move applicatoin to remote data center to perform maintenance on local data center
- Zero-downtime Data Center moves
- Move VMs and data to new data center then decommission old data center
Three Basic Configurations
- Common configurations
- Maximum supported distance, 100km (with 5ms latency)
- ESX hosts in both data centers have common IP subnets (stretched layer 2 network)
- ESX servers can participate in local HA and DRS-enabled clusters
- VMFS volume built on a VPLEX distributed device
- VMFS volume is then shared between ESX servers in two locations
- Scenario 1 (distributed device)
- Best practice
- Continuous data protection and transparently protects against storage failures in either location
- Continuous IO on biased cluster after WAN link failure
- Continuous IO on biased cluster after non-biased site failure
- Suspend IO on non-biased cluster after biased site failure
- Scenario 2 (built on remote device)
- Not highly available, only good for temporary use when VM must move immediately
- Scenario 3 (temporary distributed device)
- Storage Vmotion to a distribute device while in transit to the remote site
- Then Storage Vmotion back to local storage in the remote site
- Do this to regain some array functionality that VPLEX might not have
Failure Cases
- N+1 configuration handles director failures transparently
- Any WAN or remote cluster failure while Vmotion is in progress simply results in Vmotion being aborted
Rule-set Best Practices
- Manage your rule-sets very carefully
- Be aware of which cluster will win in the event of a failure
- Place related VMs on the same data store so that they will move together
- For any given data store, move all VMs at the same time
- For the most critical applications, dedicate a data store to the VM
