Evidian SafeKit mirror cluster with real-time file replication and failover |
| All clustering features |  |  The solution includes all clustering features:
server failure monitoring, network failure monitoring, software failure monitoring,
automatic
application
restart with a quick recovery time, a virtual IP address switched in case of failure to automatically reroute clients
 This is not the case with replication-only solutions like replication at the database level
Quick
application
restart is not ensured with full virtual machines replication. In case of hypervisor failure, a full VM must be rebooted on a new hypervisor with an unknown recovery time
The cluster configuration is very simple and made by means of a high availability application module.
There is no domain controller or active directory to configure on Windows. The solution works on Windows and Linux |
| Synchronous replication |  | The real-time replication is synchronous with no data loss on failure This is not the case with asynchronous replication |
| Fully automated failback procedure |  | After a failure when a server reboots, the replication failback procedure
is fully automatic and the failed server reintegrates the cluster without stopping
the application
on the only remaining server This is not the case with most replication solutions particularly with replication at the database level. Manual operations are required for resynchronizing a failed server.
The application
may even be stopped on the only remaining server during the resynchonization of the failed server |
| Replication of any type of data |  | The replication is working for
databases
but also for any files which shall be replicated This not the case for replication at the database level |
| File replication vs disk replication |  | The replication is based on file directories that can be located anywhere (even in the system disk) This is not the case with disk replication
where special
application
configuration must be made to put the application data in a special disk |
| File replication vs shared disk |  | The servers can be put in two remote sites This is not the case with shared disk solutions |
| Remote sites |  | All SafeKit clustering features are working for 2 servers in remote sites. Performances of replication depends on the interconnect latency for real-time synchronous replication and on the bandwidth for resynchronizing data on a failed server If both servers are connected to the same IP network through an extended LAN between two remote sites, the virtual IP address of SafeKit is working with rerouting at level 2 If both servers are connected to two different IP networks between two remote sites, the virtual IP address can be configured at the level of a load balancer.
SafeKit offers a health check: the load balancer is configured with a URL managed by SafeKit which returns OK on the primary server and NOT FOUND else. This solution is implemented for SafeKit in the Cloud but it can be also implemented with a load balancer on premise |
| Quorum |  | With remote sites, the solution works with only 2 servers and for the quorum (network isolation), a simple split brain checker to a router is offered to support a single execution This is not the case for most clustering solutions where a 3rd server is required for the quorum |
| Uniform high availability solution |  | SafeKit implements a mirror cluster with replication and failover. But it imlements also a farm cluster with load balancing and failover.
Thus a N-tiers architecture can be made highly available and load balanced with the same solution on
Windows and Linux (same installation, configuration, administration with the SafeKit console or with the command line interface). This is unique on the market This is not the case with an architecture mixing different technologies for load balancing, replication and failover |
