Interview Questions.

Q1. What Algorithms Are Used For Cache Content Replacement?

The Array(Hardware load balancer) Cache makes use of several algorithms for determining cache substitute conduct, relying at the context. In maximum cases, the Array will use LRU (Least Recently Used) to remove older content whilst space is wanted.

Q2. What Is Virtual Clustering?

Virtual clustering affords fault tolerance for VIPs among cluster contributors. For instance, if an equipment is managing visitors and it fails, every other appliance within the cluster will take over traffic processing.

Q3. What Load Balancing Methods Are Supported With Array Network Gslb ?

The Array equipment supports the following strategies for GSLB:

lc " Least connections sends customers to the website that has the least quantity of current connections.

Rr " Round robin absolutely sends patron to each site in round robin succession.

Overflow " Overflow allows requests to be sent to every other (faraway) website online whilst the nearby website is 80% loaded.

Q4. What Is Real Clustering?

Real clustering lets in all configurations from all home equipment in the cluster to be synchronized. Of course, only worldwide parameters along with the SLB configuration are synchronized. Local parameters including interface IP addresses are not synchronized.

Q5. When Load Balancing To A Real Server, Which Server Will Be Accessed First?

This relies upon on the load balancing method that you choose. Here are some examples:

Least connections (lc) method " The real server with the lowest number of concurrent connections will obtain the primary connection. Round robin (rr) technique " The actual server with the bottom access index will get the first connection. Shortest response (sr) " The loadbalancer or appliance will set up connections with each server and calculate the round journey time. The consumer connection will visit the real server with the lowest reaction time.

Q6. What Is Global Server Load Balancing (gslb)?

GSLB operates very similarly to SLB, but on a international scale. It allows you to load balance VIPs from exclusive geographical places as a single entity. This gives geographical website online fault tolerance and scalability.

Q7. What Is Health Check In Refer To Load Balancer ?

The Health Check characteristic of the load balancer that lets in you to set parameters to perform diagnostic observations at the performance of internet servers and net server farms associated with each appliance. Health checking allows you to determine if a particular server or provider is going for walks or has failed. When a service fails health tests, the SLB set of rules will forestall sending clients to that server until the service passes health checks again.

Q8. How Does Virtual Clustering Work?

In a cluster of Array appliances(h/w load balancer), one equipment turns into Master for a specific VIP and handles all visitors related to that VIP. All others live in Backup repute. If the appliance containing the Master fails, one of the appliances in Backup popularity modifications to Master reputation. Note: If multiple VIPs are configured, then Masters may be configured so that they may be allotted a number of the appliances within the cluster, supplying additional overall performance.

Q9. Does Clustering Need To Be Turned On In Order To Use Gslb?

Yes, Clustering should be configured and grew to become on which will use GSLB. Each proxy in the web page (or cluster) ought to have the identical configuration. Hence, every appliance can act as a DNS server if it will become a grasp for the web page. Each website may have a unique cluster/SLB/GSLB configuration, and you will use the gslb web site overflow command to feature the remote GSLB web site to the nearby appliance.

Q10. What Is The Purpose Of Content Rewrite?

The Content Rewrite characteristic lets in CDN (Content Distribution Network) reference strings to be dynamically inserted into URLs that are embedded in net pages. With admire to at least one precise CDN, the time period "linux" refers back to the rewriting of embedded URLs to point to ubuntu-linux"s community.

Q11. What Is Recursion Depth?

In a tree shape, it refers back to the range of ranges that can be traversed underneath the primary or figure web page. This is regularly used to specify how tons of a web site (what number of levels deep) to preload into the cache.

Q12. What Is The Difference Between A Persistent Cookie Policy And A Qos Cookie Policy In Array Network Loadbalancer ?

A Persistent Cookie policy selects a collection primarily based on the cookie name. A QoS Cookie policy selects a server group based totally at the cookie name and value assigned to that institution.

Q13. What Is Reverse Proxy Cache?

Reverse Proxy Cache is a cache this is in front of the origin servers, subsequently the usage of the term reverse inside the name. If a purchaser requests a cached object, the proxy will carrier the request from the cache in place of the beginning server.

Q14. What Is Meant By Dynamic And Static Content? Can My Array Appliance Cache Dynamic Content?

When a purchaser requests an internet web page, a web server returns the asked content material. If the content material is retrieved from disk/memory and lower back to the client without similarly processing, the content material is said to be static. If the content material is generated on-the-fly by the server (e.G., based on database facts), it is called dynamic content.

Q15. How Does The Cache Decide What To Cache?

The HTTP Cache-Control header determines the cacheability of the item and can also determine how long the object should be cached. The cache may be configured to override the cacheability of an object by using specifying the hostname and a normal expression that fits within the URL of the object.

Q16. What Information Needs To Be Provided In Order To Set Up My Appliance To Do Cookie Load Balancing?

You need the cookie call, cookie values, the VIP to bind to, and the businesses to balance to.

Q17. What Is Server Load Balancing?

Server Load Balancing (SLB) gives network overall performance and content transport by means of enforcing a chain of algorithms and priorities to reply to the specific requests made to the community. In easy phrases, SLB distributes clients to a collection of servers and ensures that customers are not despatched to failed servers.

Q18. What Parameters Need To Be Defined In The Cluster Configuration?

Cluster ID, VIP deal with, interface (Outside or Inside), priorities, and authorization technique (password or none) ought to be described. Preempt and mrthresh are optionally available.