myEvolv Web Server Technical Requirements
These requirements are for a web server in the myEvolv client-server infrastructure.
Web Server
|
|
Small (1-49 users) |
Medium (50-199 users) |
Large - High Availability (200+ users) |
|---|---|---|---|
| Number of Hosts | 1 | 1* | 2 (See section on Load Balancing) |
|
Processor |
Intel® Xeon™ Processor, 2.8GHz or Greater - 2 cores | Intel® Xeon™ Processor, 2.8GHz or Greater - 2 cores | Intel® Xeon™ Processor, 2.8GHz or Greater - 2 cores |
|
Memory |
**4GB for OS + 2GB per application pool | **4GB for OS + 2GB per application pool | **4GB for OS + 2GB per application pool |
|
Disk Array |
RAID Controller |
RAID Controller |
RAID Controller |
|
Hard Drive |
146GB 10K or 15K RPM SCSI Hard Drives (Quantity of 2 – RAID 1 configuration) |
146GB 10K or 15K RPM SCSI Hard Drives (Quantity of 2 – RAID 1 configuration) |
146GB 10K or 15K RPM SCSI Hard Drives (Quantity of 2 – RAID 1 configuration) |
|
Network |
TCP/IP Network Adapter 100Mbps (12.2 MB) or greater |
TCP/IP Network Adapter 100Mbps (12.2 MB) or greater |
TCP/IP Network Adapter 100Mbps (12.2 MB) or greater |
|
OS |
Windows Server® 2008/2012 R2 X64 |
Windows Server® 2008/2012 R2 X64 |
Windows Server® 2008/2012 R2 X64 |
|
Power |
Redundant Power Supplies |
Redundant Power Supplies |
Redundant Power Supplies |
| Web Server | IIS 7.5/8.5 | IIS 7.5/8.5 | IIS 7.5/8.5 |
| Other |
MDAC .Net Framework 4.7.2 |
MDAC .Net Framework 4.7.2 |
MDAC .Net Framework 4.7.2 |
* The number of web server hosts required depends on the usage characteristics of each system. If the web server regularly encounters "out of memory" events visible in IIS requests logs as well as in the Event Viewer, Netsmart recommends scaling out the web tier by adding an additional host. With a multi-server web tier, load balancing is required.
** Additional memory may be required if the web server is running additional applications.
Note: If you need assistance from a Netsmart System Engineer please contact your client alignment executive (CAE) for technical consulting services.
Load Balancing
Session Persistence
For a load balanced configuration with two or more web servers, myEvolv requires that the load balancer supports session persistence. Session persistence ensures that users connects to the same web server for the duration of their session. Session persistence can be handled by a load balancer through a variety of methods, one example would be cookie based session persistence, where the load balancer generates a cookie to track individual sessions.
Note: A solution which uses client affinity by network address (such as Microsoft NLB) may also work, however one caveat to this method is that client source IPs must not be SNATed. Unique client IPs would not be visible to the load balancer, resulting in all traffic being directed to a single web server. To provide an example if we have 25 users accessing the site from the internet, where each unique user would have a unique source IP; a firewall would change the source IP of the internet users to its single internal IP. NLB would see all of the traffic as coming from one single IP, and would not be able to balance the load between multiple servers. In this same scenario where the firewall is SNATing the client IP addresses, cookie persistence would ensure that individual clients are load balanced accordingly, regardless of source IP address.
Load Balancing Algorithm
A load balancing algorithm that dynamically distributes load based on observed connections is recommended. Basic round-robin style load balancing is not recommended because of the need for session persistence.