The Array(Hardware load balancer) Cache uses several algorithms for determining cache replacement behavior, depending on the context. In most cases, the Array will use LRU (Least Recently Used) to remove older content when space is needed.
Virtual clustering provides fault tolerance for VIPs among cluster members. For example, if an appliance is handling traffic and it fails, another appliance in the cluster will take over traffic processing.
The Array appliance supports the following methods for GSLB:
Real clustering allows all configurations from all appliances in the cluster to be synchronized. Of course, only global parameters such as the SLB configuration are synchronized. Local parameters such as interface IP addresses are not synchronized.
This depends on the load balancing method that you select. Here are a few examples:
Least connections (lc) method " The real server with the lowest number of concurrent connections will receive the first connection. Round robin (rr) method " The real server with the lowest entry index will get the first connection. Shortest response (sr) " The loadbalancer or appliance will establish connections with each server and calculate the round trip time. The client connection will go to the real server with the lowest response time.
GSLB operates very similarly to SLB, but on a global scale. It allows you to load balance VIPs from different geographical locations as a single entity. This provides geographical site fault tolerance and scalability.
The Health Check feature of the load balancer that allows you to set parameters to perform diagnostic observations on the performance of web servers and web server farms associated with each appliance. Health checking allows you to determine if a particular server or service is running or has failed. When a service fails health checks, the SLB algorithm will stop sending clients to that server until the service passes health checks again.
In a cluster of Array appliances(h/w load balancer), one appliance becomes Master for a particular VIP and handles all traffic related to that VIP. All others stay in Backup status. If the appliance containing the Master fails, one of the appliances in Backup status changes to Master status. Note: If multiple VIPs are configured, then Masters can be configured so that they are distributed among the appliances in the cluster, providing additional performance.
Yes, Clustering must be configured and turned on in order to use GSLB. Each proxy within the site (or cluster) must have the same configuration. Hence, each appliance can act as a DNS server if it becomes a master for the site. Each site will have a unique cluster/SLB/GSLB configuration, and you will use the gslb site overflow command to add the remote GSLB site to the local appliance.
The Content Rewrite function allows CDN (Content Distribution Network) reference strings to be dynamically inserted into URLs that are embedded in web pages. With respect to one particular CDN, the term "linux" refers to the rewriting of embedded URLs to point to ubuntu-linux"s network.
In a tree structure, it refers to the number of levels that can be traversed below the main or parent page. This is often used to specify how much of a web site (how many levels deep) to preload into the cache.
A Persistent Cookie policy selects a group based on the cookie name. A QoS Cookie policy selects a server group based on the cookie name and value assigned to that group.
Reverse Proxy Cache is a cache that is in front of the origin servers, hence the use of the term reverse in the name. If a client requests a cached object, the proxy will service the request from the cache instead of the origin server.
When a client requests a web page, a web server returns the requested content. If the content is retrieved from disk/memory and returned to the client without further processing, the content is said to be static. If the content is generated on-the-fly by the server (e.g., based on database data), it is referred to as dynamic content.
The HTTP Cache-Control header determines the cacheability of the object and can also determine how long the object should be cached. The cache can be configured to override the cacheability of an object by specifying the hostname and a regular expression that matches within the URL of the object.
You need the cookie name, cookie values, the VIP to bind to, and the groups to balance to.
Server Load Balancing (SLB) provides network performance and content delivery by implementing a series of algorithms and priorities to respond to the specific requests made to the network. In simple terms, SLB distributes clients to a group of servers and ensures that clients are not sent to failed servers.
Cluster ID, VIP address, interface (Outside or Inside), priorities, and authorization method (password or none) must be defined. Preempt and mrthresh are optional.