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Showing posts from December, 2016

What is storage area networks used for?

SANs are primarily used to enhance storage devices, such as disk arrays, tape libraries, and optical jukeboxes, accessible to servers so that the devices appear to the operating system as locally attached devices.
A SAN typically has its own network of storage devices that are generally not accessible through the local area network (LAN) by other devices.  The cost and complexity of SANs dropped in the early 2000s to levels allowing wider adoption across both enterprise and small to medium-sized business environments.

A SAN does not provide file abstraction, only block-level operations. However, file systems built on top of SANs do provide file-level access, and are known as shared-disk file systems.

More to read:
Best SAN Storage area networks acronymsTop 20 benefits of SAN Storage area networks

My selected top books you need now for success

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Devote 10 percent of your time and capital to pursuing your dream, McGinnis says, and you can keep your job and the security that goes with it. McGinnis, who identifies himself as a 10-percenter, provides a detailed plan to identify a promising first project. He shows how to invest resources in a savvy way, and how to develop something you love doing into a business. Best of all, until you reach your dream of an independent business, McGinnis promises you will perform better at your day job with a step-by-step plan.

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The unique helpful SAN architecture simplified one

Storage Area Networks (SANs)

A SAN is connected behind the servers. SANs provide block-level access to shared data storage. Block level access refers to the specific blocks of data on a storage device as opposed to file level access. One file will contain several blocks. 

SANs provide high availability and robust business continuity for critical data environments. SANs are typically switched fabric architectures using Fibre Channel (FC) for connectivity. The term switched fabric refers to each storage unit being connected to each server via multiple SAN switches also called SAN directors which provide redundancy within the paths to the storage units. This provides additional paths for communications and eliminates one central switch as a single point of failure.Ethernet has many advantages similar to Fibre Channel for supporting SANs. Some of these include high speed, support of a switched fabric topology, widespread interoperability, and a large set of management tools. In a storage ne…

Top Storage Area networks selected Acronyms for interviews

These are most popular terms used in Storage area networks area. Every developer must know these terms clearly. Highly useful to explain in interviews.

SAN Network

Fibre channel - Fibre channel denotes a fibre-optical connection to a device or component. This is typically abbreviated as FC.
Host bus adapter - A host bus adapter is used by a given machine to access a storage area network. A host bus adapter is similar in function to a network adapter and how it provides access for a machine to a local area network or wide area network. This is typically abbreviated as HBA.

Storage area network - A storage area network is a network of shared devices that can typically be accessed using fibre. Often, a storage area network is used to share devices between many different machines. This is typically abbreviated as SAN
SAN Configurations

Point to point - This is the simplest configuration. The devices are connected directly to the HBA.

Arbitrated loop - Arbitrated loop topologies are ring topologi…

The SAN key benefits how useful for larger organizations

SANs are particularly helpful in backup and disaster recovery settings. Within a SAN, data can be transferred from one storage device to another without interacting with a server.  This speeds up the backup process and eliminates the need to use server CPU cycles for backup. Also, many SANs utilize Fibre Channel technology or other networking protocols that allow the networks to span longer distances geographically.
That makes it more feasible for companies to keep their backup data in remote locations.Utilizing a SAN can also simplify some management tasks, potentially allowing organizations to hire fewer IT workers or to free up some IT workers for other tasks. It's also possible to boot servers from a SAN, which can reduce the time and hassles involved in replacing a server. Advantages-Before the advent of SANs, organizations generally used direct-attached storage (DAS). As the name implies, direct-attached storage is directly attached to the server, residing either on the server …

Top 20 ultimate ETL Questions really good for interviews

How to print/display the first line of a file?  there are many ways to do this. However the easiest way to display the first line of a file is using the [head] command.  $> head -1 file. Txt no prize in guessing that if you specify [head -2] then it would print first 2 records of the file.  another way can be by using [sed] command. [sed] is a very powerful text editor which can be used for various text manipulation purposes like this.  $> sed '2,$ d' file. Txt how does the above command work?  The 'd' parameter basically tells [sed] to delete all the records from display from line 2 to last line of the file (last line is represented by $ symbol). Of course it does not actually delete those lines from the file, it just does not display those lines in standard output screen. So you only see the remaining line which is the 1st line.  how to print/display the last line of a file?  the easiest way is to use the [tail] command.  $> tail -1 file. Txt if you want to do it using…

The most popular tools for your data mining needs

There are many tools available for data mining. For only backup just look at  The best Free mining tool that adds value to backup data. The listed are more popular tools.
Rapid Miner (erstwhile YALE): 

This is very popular since it is a ready made, open source, no-coding required software, which gives advanced analytics. Written in Java, it incorporates multifaceted data mining functions such as data preprocessing, visualization, predictive analysis, and can be easily integrated with WEKA and R-tool to directly give models from scripts written in the former two.


This is a JAVA based customization tool, which is free to use. It includes visualization and predictive analysis and modeling techniques, clustering, association, regression and classification.

R-Programming Tool:

This is written in C and FORTRAN, and allows the data miners to write scripts just like a programming language/platform. Hence, it is used to make statistical and analytical software for data mining. It supports gra…

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The best Free mining tool that adds value to backup data

What is data mining? The next big thing in backup will be a business use case to mine the data being stored for useful information. It’s a shame all that data is just sitting there wasted unless a restore is required. It should be leveraged for other, more important things. This method is called Data Mining Technique. For example, can you tell me how many instances of any single file is being stored across your organization? Probably not, but if it’s being backed up to a single-instance repository, the repository stores a single copy of that file object, and the index in the repository has the links and metadata about where the file came from and how many redundant copies exist. By simply providing a search function into the repository, you would instantly be able to find out how many duplicate copies exist for every file you are backing up, and where they are coming from.
Knowing this information would give you a good idea of where to go to delete stale or useless data. The complete kn…

The best SAN applications being used in real time

The storage area network fundamentals everyone must know you understand about applications. These applications may refer to horizontal applications (e.g., backup, archiving, data replication, disaster protection, and data warehousing) or vertical applications (e.g., online transaction processing (OLTP), enterprise resource planning (ERP) business applications, electronic commerce, broadcasting, prepress, medical, and geophysics).
SAN is also well suited to making performance and high availability more scalable and more affordable in applications such as clustering and data sharing. This article discusses two major horizontal applications, backup and data sharing, and how they interact with SAN. The other important point is, if you are a job seeker the below list is helpful. This is just a like a one time SAN interviews refresher. So you can do well in interviews.

Realtime (or window-less) backup: The importance of window-less backup (also called hot backup) becomes obvious when it add…

20 top SAN storage area networking crucial benefits

In my previous post I have covered about fundamentals of SAN(storage area networks). The below are the list of top 20 benefits of storage area networks.

Greater performance: Current Fibre Channel SANs allow connection to disks at hundreds of megabytes per second; the near future will see speeds in multiple gigabytes to terabytes per second.

Increased disk utilization: SANs enable more than one server to access the same physical disk, which lets you allocate the free space on those disks more effectively. Higher availability to storage by use of multiple access paths: A SAN allows for multiple physical connections to disks from a single or multiple servers.

Deferred disk procurement: That’s business-speak for not having to buy disks as often as you used to before getting a SAN. Because you can use disk space more effectively, no space goes to waste.

Reduced data center rack/floor space: Because you don’t need to buy big servers with room for lots of disks, you can buy fewer, smaller server…

Storage are networking speed devices way to configuration

In today’s terms, the technical description of a SAN (Storage Area Network) is a collection of computers and storage devices, connected over a high-speed optical network and dedicated to the task of storing and protecting data. In a nutshell, you use a SAN to store and protect data. A SAN uses the SCSI (Small Computer Storage Interconnect) and FC (Fibre Channel) protocols to move data over a network and store it directly to disk drives in block format.

Today, that high-speed network usually consists of fiber-optic cables and switches that use light waves to transmit data with a connection protocol known as Fibre Channel. (A protocol is a set of rules used by the computer devices to define a common communication language.) More and more, regular Internet protocol (IP)–based corporate networks, and even the Internet, are being used as the network part of a SAN. IP networks that are already in place can be used by other storage connection protocols such as iSCSI (internet Small Computer …

The complete list of R Data types and structures

To make the best of the R language, you'll need a strong understanding of the basic data types and data structures and how to operate on those. Very Important to understand because these are the things you will manipulate on a day-to-day basis in R. Everything in R is an object.
The basic data types  logical (e.g., TRUE, FALSE)integer (e.g,, 2L, as.integer(3))numeric (real or decimal) (e.g, 2, 2.0, pi)complex (e.g, 1 + 0i, 1 + 4i)character (e.g, "a", "swc") The basic data structures in R vectorlistmatrixdata framefactorstables Vector in R A vector is the most common and basic data structure in R and is pretty much the workhorse of R.  Vectors can be of two types: atomic vectorslists

The best 5 points that you can do with R

As a R developer in data analytics you should know what all the key points you can do with R language. R is very prominent language it can be used very much in data science.

Vectors and assignment
R operates on named data structures. The simplest such structure is the numeric vector, which is a single entity consisting of an ordered collection of numbers. To set up a vector named x,say, consisting of five numbers, namely 10.4, 5.6, 3.1, 6.4 and 21.7, use the R command
> x <- 21.7="" 3.1="" 5.6="" 6.4="" c="" p="">This is an assignment statement using the function c() which in this context can take an arbitrary number of vector arguments and whose value is a vector got by concatenating its arguments end to end.

Reading data from files
Large data objects will usually be read as values from external files rather than entered during an R session at the keyboard. R input facilities are simple and their requirements are fai…

How to write R Script in simple way

A script is a good way to keep track of what you're doing. If you have a long analysis, and you want to be able to recreate it later, a good idea is to type it into a script. If you're working in the Windows R GUI (also in the Mac R GUI), there is even a built-in script editor. To get to it, pull down the File menu and choose New Script (New Document on a Mac). A window will open in which you can type your script. R Script is a series of commands that you can execute at one time and you can save lot of time. script is just a plain text file with R commands in it. How to create R Script You can prepare a script in any text editor, such as vim, TextWrangler, or Notepad. You can also prepare a script in a word processor, like Word, Writer, TextEdit, or WordPad, PROVIDED you save the script in plain text (ascii) format. This should (!) append a ".txt" file extension to the file. Drop the script into your working directory, and then read it into R using the source() function. J…

What is data lake and how it works

A data lake is a method of storing data within a system or repository, in its natural format,that facilitates the collocation of data in various schemata and structural forms, usually object blobs or files.

Traditional database theory dictates that you design the data set before entering any data. A data lake, also called an enterprise data lake or enterprise data hub. Then get all these data sources and dump them all into a big Hadoop repository, and you won’t try to design a data model beforehand. Instead, it provides tools for people to analyze the data, along with a high-level definition of what data exists in the lake. eople build the views into the data as they go along. It’s a very incremental, organic model for building a large-scale database.

As part of its Intuit Analytics Cloud, Intuit has a data lake that includes clickstream user data and enterprise and third-party data. But, the focus is on “democratizing” the tools surrounding it to enable business people to use it eff…