STRATO Load Balancing Product description Version: May 2015

(1)

STRATO AG | www.strato.com | STRATO Load Balancing | Version: 1505.1

STRATO Load Balancing

Product description

Version: May 2015

2

1 STRATO Load Balancing

STRATO Load Balancing offers you the possibility to set up a load distribution on two or more servers. The load distribution makes it possible for you to direct incoming and outgoing network traffic through the STRATO Load Balancer. This distributes the traffic to the participating server depending on the weighting.

2 Possible usage scenarios

The usage possibilities are versatile. The following scenarios should provide an impression as to which application cases can be realized. The actual constellation always depends on the concrete requirements. Our technicians are gladly available for any customer inquiries.

2.1 Load distribution and increase of availability

In this scenario, you operate at least two servers, which provide services as real servers (in load balancing).

Neither a STRATO ProNet VLAN nor a STRATO ProStorage iSCSI SAN is required. The data synchronization is carried out through the first network interface. The scenario is suitable for delivering static websites. If a real server fails, the other real servers take over the delivery of the websites.

Example request You need high stability and load distribution for mostly static web content.

The solution In addition to your servers, order one of the two load balancing packages. Add the load balancing to your server as a real server. Server content can be best

synchronized at times in which only a few inquiries are received - for example, nightly synchronization of databases.

STRATO Load Balancing

Platform

(3)

3 2.2 Load distribution, increase of availability and session synchronization

In this scenario, you operate at least two servers, which provide services as real servers (in load balancing). The participating servers are connected with each other through a STRATO ProNet VLAN through which the heartbeat information is shared and the data is synchronized.

Example request You need high stability and load distribution for static and dynamic web content. Additionally, session information should be synchronized between the real servers.

The solution Order a STRATO ProNet VLAN in addition to the Load Balancer. This can be used to share heartbeat information and execute the data synchronization. Since no central storage is available in this scenario, session information must be kept in the storage and synchronized through ProNet VLAN. Through in-memory session synchronization, for example, shopping carts or forums can be created.

STRATO ProNet VLAN Real server STRATO Load Balancing Platform

(4)

4 2.3 Additional simultaneous access to central data

In this scenario, you operate a highly frequented website. The load that exists through the frequent website views is CPU intensive and can be distributed on the real server.

If the computing power from the real server is inadequate, you can simply provide for optimal performance without the tedious synchronization of databases by adding another server.

Example request Primarily increasing the performance of your website is in focus here. The secondary goal is to increase availability and flexibility.

The solution The real servers are connected with the STRATO ProStorage iSCSI SAN through the STRATO ProNet VLAN and simultaneously access the same database (the current Linux images from the STRATO root server offer the support of a cluster file system required for this). The requests are distributed to the servers through the load balancing on the real server. Both session information as well as statically and dynamically generated web content can be saved centrally on the ProStorage iSCI SAN.

STRATO ProNet VLAN Real server STRATO Load Balancing Platform STRATO ProStorage iSCSI SAN

(5)

5

3 Terms

Service A service is a TCP socket. Incoming connections from the internet to the load balancer IP are forwarded to the configured real server by the STRATO Load Balancing platform.

iSCSI iSCSI is a transfer protocol that allows for the usage of the SCSI protocol, which is used for hard drives, through normal TCP networks. iSCSI devices (targets) can be contacted, formatted and used like local hard drives. The targets are integrated through a software program, the so-called initiator.

Load Balancer A Load Balancer is the network device (appliance) that is responsible for the distribution of the data traffic. For reasons of redundancy, the STRATO Load Balancing platform consists of four load balancers. The platform is based on the Linux Virtual Server Project (LVS) and the Keepalived Framework, which implements the health checking for LVS.

Load Balancer IP The services that are offered in STRATO load balancing can be reached from the internet under this IP address.

Load Balancing Load balancing is the distribution of connection oriented data traffic to two or multiple servers.

Private IP network Private IP addresses are not routed in the internet. They serve exclusively for communication within the STRATO data center or the STRATO data centers, for example, for the communication between load balancers and connected real servers in a STRATO ProNet VLAN or with STRATO load balancing.

Real server A real server is a server that provides one or several services for STRATO Load Balancing.

Shared Load Balancing With Shared Load Balancing, several customers use the same load balancing infrastructure. The STRATO Load Balancing platform provides shared load balancing.

VLAN A Virtual Local Area Network (VLAN) is a virtual local network within a physical, switched network environment.

4 Product details for STRATO Load Balancing

The STRATO Load Balancing product allows you to use a central, shared, high-power, stable load balancing platform. The platform and the required infrastructure are offered by STRATO as managed services. STRATO takes care of the operation, maintenance and administration of the systems. Configuration possibilities provided by STRATO, if not described differently, are offered in the STRATO Customer Service Area.

Customers who use two or more dedicated servers will be given the option to set up a load distribution for the TCP data traffic. Here all of the connection-oriented services from the load balancing are supported that only use a TCP port for communication.

The load balancing serves to increase the performance and availability of services like HTTP and HTTPS. Services can be provided by several servers instead of just one single server. Incoming client requests from the internet initially reach a load balancer, which then distributes these to the real servers, which in turn process the requests. Thus, the service can be accessed by the client from the internet under a central IP address, the

(6)

6

Load Balancer IP, and the overall performance can be scaled with the number of available real servers. The Load Balancer monitors the functionality of the real servers on a minute basis and only considers functional real servers for load balancing. Through this, the stability is increased compared to an individual server. The distribution of the data traffic is carried out solely according to the weighted ring distribution procedure (weighted round robin, WRR). You can set the weighting of the distribution in the Customer Service Area in order to consider different capabilities of the real server. With this procedure, a scheduling sequence is created in which the individual real servers are found multiple times corresponding to their weighting.

Example: If the real servers A, B and C are present with the weights 4, 3 and 2, the load balancer will create the sequence AABABCABC in which the real servers are found as often as specified by their weight. Round robin distribution is applied to this sequence once it has been determined.

With the STRATO Service Level Agreements, target availabilities of up to 99.99% (monthly average) are guaranteed for the STRATO Load Balancer Core Network.

4.1 Scalability

The number of configurable services and the number of real servers that can be added are determined through the package selection. If different requirements exist for your application, our technicians are gladly available to help you out.

4.2 Usable protocols

The STRATO Load Balancing platform supports connection-oriented services, which process their

communication through an individual TCP port. Connection-free communication via UDP and connection-oriented communication through several TCP ports, for example, with FTP and SIP, are not supported.

4.3 Usable distribution algorithms

The STRATO Load Balancing platform exclusively uses the weighted ring distribution algorithm (weighted round robin, WRR algorithm) as an algorithm for the distribution of data.

4.4 Usability of the service

Only servers that are located in the STRATO data center may participate in the load balancing. The usability is provided subject to a technical inspection by STRATO.

(7)

7

5 STRATO Security Concept

STRATO places the greatest value in security and availability. That is why we do everything to completely protect you and your website visitors from all types of risks. You are always on the safe side with STRATO. The topics of data protection and data security have never been so relevant. With STRATO products, you can relax and concentrate on what is most important. Our excellent IT security, our data protection and availability are verified repeatedly each year through independent TÜV certification (ISO 27001). STRATO offers you a three-tiered security concept that leaves nothing to be desired.

STRATO Load Balancing Product description Version: May 2015