When implementing high availability, a key decision is whether to protect at the virtual machine (VM) level or at the application level. VM-level HA replicates and fails over entire virtual machines, providing a generic solution for any application. Application-level HA targets only the application data and services, resulting in faster recovery times and lower resource usage. SafeKit uniquely offers both approaches — without requiring shared storage (SAN) in either case — allowing you to choose the best fit for your infrastructure and recovery requirements.
| Criteria | VM HA with SafeKit Hyper-V or KVM module | Application HA with SafeKit application modules | Microsoft Hyper-V Cluster & VMware HA |
|---|---|---|---|
| Architecture | SafeKit installed inside 2 hypervisors. Replication and failover of the full VM. | SafeKit installed inside 2 virtual or physical machines. Replication and failover at application level. | Hypervisor cluster with shared storage. VM restart on another host if the hypervisor fails. |
| Storage | No shared disk — synchronous real-time replication with no data loss | No shared disk — synchronous replication of application data only | Requires a shared disk and a specific external bay of disks |
| Data replicated | Replicates more data (application + OS) | Replicates only application data | No replication — shared storage accessed by all hosts |
| Recovery time | Reboot of the VM on hypervisor 2 if hypervisor 1 crashes. Recovery time = time to reboot the VM. Failover if the VM crashes. | Quick recovery with restart of the application on server 2. Around 1 minute or less (see RTO/RPO here). Advanced application checker and software failover. | Full VM reboot on a new hypervisor. Recovery time depends on OS reboot + application startup. |
| Disaster recovery / Remote sites | No SAN needed — replication built into SafeKit across remote sites | No SAN needed — replication built into SafeKit across remote sites | Requires replicated bays of disks across a SAN or vSAN |
| Configuration | Define the location of the VM files folder where the application is installed. Generic solution for any application/OS. | Define services to restart, application folders to replicate, and a virtual IP address for failover inside an application module. | Specific IT skills required to configure the system |
| Supported platforms | Works with Hyper-V and KVM (not VMware directly, except by nesting Hyper-V or KVM inside VMware). | Works in any infrastructure: physical servers, VMware, Hyper-V, KVM virtual machines, cloud. | Limited to VMware vSphere or Microsoft Hyper-V environments |
| IT skills | No specific IT skill required. Automatic failover. | No specific IT skill required. Automatic failover. | Specific IT skills required to configure the system |