Microsoft NLB in VMware: alternative to multicast and unicast with the SafeKit software - Evidian

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Microsoft NLB in VMware: alternative to multicast and unicast with the SafeKit software

Alternative with the virtual IP address of Evidian SafeKit

With the SafeKit software, network load balancing is implemented by filtering packets in the network stacks as with Microsoft NLB. The virtual IP address is set as an alias IP address on the NIC card of each physical or virtual machine. A single network is sufficient to implement network load balancing.

The virtual IP address configuration does not require any special network configuration and the network load balancing can run in any environment (thanks to the vmac_directed technology). An important feature when the solution must be deployed in an unknown infrastructure: unknown switches or routers, physical servers or virtual servers.

Note that the solution is available on Windows and Linux (even on Windows editions for PCs).

Best practices of a farm cluster with load balancing and failover

Evidian SafeKit farm cluster with load balancing and failover
No load balancer or dedicated proxy servers or special multicast Ethernet address		The solution does not require load balancers or dedicated proxy servers above the farm for imlementing load balancing. SafeKit is installed directly on the application servers in the farm. The load balancing is based on a standard virtual IP address/Ethernet MAC address and is working with physical servers or virtual machines on Windows and Linux without special network configuration This is not the case with network load balancers This is not the case with dedicated proxies on Linux This is not the case with a specific multicast Ethernet address on Windows
All clustering features		The solution includes all clustering features: virtual IP address, load balancing on client IP address or on sessions, monitoring of server/network/software failures, automatic application restart with a quick revovery time and a replication option with a mirror module This is not the case with other load balancing solutions. They are able to make load balancing but they do not include a full clustering solution with restart scripts and automatic application restart in case of failure. They do not offer a replication option The cluster configuration is very simple and made by means of application modules. There is no domain controller or active directory to configure on Windows. The solution works on Windows and Linux
Remote sites		If servers are connected to the same IP network through an extended LAN between remote sites, the virtual IP address of SafeKit is working with load balancing at level 2 If servers are connected to different IP networks between 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 UP servers 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. Thus you can implement load balancing but also all the clustering features of SafeKit including an easy administration of the cluster through the SafeKit web console
Uniform high availability solution		SafeKit imlements a farm cluster with load balancing and failover. But it implements also a mirror cluster with replication 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

Compare high availability clusters

High availability architectures comparison
Feature	SafeKit cluster	Other clusters
Software clustering vs hardware clustering More information...	A simple software cluster with the SafeKit package just installed on two servers	Complex hardware clustering with external storage or network load balancers
Shared nothing vs a shared disk cluster More information...	SafeKit is a shared-nothing cluster: easy to deploy even in remote sites	A shared disk cluster is complex to deploy
Application High Availability vs Full Virtual Machine High Availability More information...	Application HA supports hardware failure and software failure with a quick recovery time (RTO around 1 mn or less). Smooth upgrade of application and OS possible server by server (version N and N+1 can coexist)	Full virtual machines HA supports only hardware failure with a VM reboot and a recovery time depending on the OS reboot. Smooth upgrade not possible
High availability vs fault tolerance	No dedicated server. Each server can be the failover server of the other one. Software failure with restart in another OS environment. Smooth upgrade of application and OS possible server by server (version N and N+1 can coexist)	Secondary server dedicated to the execution of the same application synchronized at the instruction level. Software exception on both servers at the same time. Smooth upgrade not possible
Synchronous replication vs asynchronous replication More information...	SafeKit implements real-time synchronous replication with no data loss in case of failure	With asynchronous replication, there is data loss on failure
Byte-level file replication vs block-level disk replication More information...	SafeKit implements real-time byte-level file replication and is simply configured with application directories to replicate even in the system disk	Block-level disk replication is complex to configure and requires to put application data in a special disk
Heartbeat, failover and quorum to avoid 2 master nodes More information...	To avoid 2 masters, SafeKit proposes a simple split brain checker configured on a router	To avoid 2 masters, other clusters require a complex configuration with a third machine, a special quorum disk, a special interconnect
Network load balancing More information...	No dedicated proxy servers and no special network configuration are required in a SafeKit cluster for network load balancing	Special network configuration is required in other clusters for network load balancing

Real-time file replication and failover: click on the blue buttons
Mirror modules	Windows	Linux
Microsoft SQL Server		-
Oracle
MySQL
PostgreSQL
Firebird
Hyper-V		-
Milestone XProtect		-
Hanwha Wisenet SSM		-
New application
Amazon AWS mirror
Microsoft Azure mirror
Google GCP mirror
Cloud generic mirror