As a Reverse Proxy | Supported and Tested - The major advantage of using IBM HTTP Server is that a single server can be used as a Reverse Proxy and as the Load Balancer |
Not Tested or Supported as a Reverse Proxy - HAProxy is tested as a Load Balancer ONLY for RTC clustered setup in combination with IBM HTTP Server as a Reverse proxy |
IBM HTTP SERVER | HAPROXY | |
---|---|---|
Support | IBM Support | Forum Support (Community Edition) - IBM Support Policy on Third party and Open Source software - IBM has documented instructions on installation and configuration of HAProxy in the context of deploying a Clustered Setup of RTC |
Operating Systems | Can be installed on Windows, Linux and AIX Platforms | Can be installed on Linux Platforms Only |
CLM Versions | Supported as a Load Balancer from CLM/CE version 6.0.5 Onwards | Supported as a Load Balancer from CLM/CE 6.0.4 Onwards |
Load Balancing | The following Load Balancing Policies are support by IHS, The default load balancing type is Round Robin. Round Robin - The Round Robin implementation has a random starting point. The first application server is picked randomly. Round Robin is then used to pick application servers from that point forward. This implementation ensures that in multiple process-based web servers, all of the processes do not start by sending the first request to the same Application Server. Random The Random implementation also has a random starting point. However with this implementation all subsequent servers are also randomly selected. Therefore, the same server might get selected repeatedly while other servers remain idle. |
HAProxy supports a rich set of Load Balancing algorithms and the default is Leastconn. Following are a few examples: Round Robin - Each server is used in turns, according to their weights. This algorithm is dynamic, which means that server weights may be adjusted on the fly for slow starts for instance. Note that in some large farms, when a server goes up after having been down for a very short time, it may sometimes take a few hundreds requests for it to be re-integrated into the farm and start receiving traffic. This is normal, though very rare. It is indicated here in case you would have the chance to observe it, so that you don't worry. Static Round Robin - Each server is used in turns, according to their weights. This algorithm is as similar to roundrobin except that it is static, which means that changing a server's weight on the fly will have no effect. On the other hand, when a server goes up, it is always immediately reintroduced into the farm, once the full map is recomputed. It also uses slightly less CPU to run (around -1%). Leastconn - The server with the lowest number of connections receives the connection. Round-robin is performed within groups of servers of the same load to ensure that all servers will be used. This algorithm is dynamic, which means that server weights may be adjusted on the fly for slow starts for instance. Source -The source IP address is hashed and divided by the total weight of the running servers to designate which server will receive the request. This ensures that the same client IP address will always reach the same server as long as no server goes down or up. This algorithm is static by default, which means that changing a server's weight on the fly will have no effect, but this can be changed using "hash-type". |
High Availability | YES | YES |
Monitoring | External Tools can be used | Statistics Reports is Bundled with HAProxy UI. External Tools can be used as well |