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Posts Tagged ‘nfs’

Knowing NFS

February 23rd, 2012 No comments

Making use of NFS, clients will mount the partitions of server like they were connected physically to client. Besides, simply allowing the remote access to the files over network, the NFS allows relatively low cost systems to share similar high capacity drive simultaneously. The NFS server software’s are written for a lot of different operating systems that allow the users on the UNIX workstations to have a remote access to the files that are stored on various platforms. The NFS costumers are written for the microcomputers like IBM/PC & Apple Macintosh, and giving the PC users same flexibility to be enjoyed by the UNIX coworkers, and relatively simple method of the data interchange.

 

File Handles

Every object on NFS mounted file system is been referenced by the unique object named file handle. The file handle is been viewed by a client as opaque – client will not interpret contents. But, to server, contents have some meaning. File handles identify each directory and file on server computer. Under UNIX, the file handle comprises of 3 important elements: file system identifier, file identifier, as well as generation count. File identifier is something as easy as the inode number for referring to the particular item on partition. File system identifier generally refers to partition having the file (the inode numbers are very unique every partition, however not system). File handle does not include the pathname; pathname isn’t necessary as well as is subject to get change whereas the file is accessed.

 

Generation count is the number, which is incremented every time the file is recreated and unlinked. Generation count makes sure when the client references the file on server, file is actually same file that server thinks. Without the generation count, 2 clients accessing same file on a server can make erroneous results in case, one costumer deleted a file and made the new file with same inode number. Generation count stops these situations from happening: when file is recreated, generation number is also incremented, and second client gets the error message while it attempts on accessing older, and now nonexistent, file.

 

In case, NFS client doesn’t get the acknowledgment, then the UDP lost either original RPC command or the RPC acknowledgment. In case, original RPC command is lost, then there is not any problem – server sees that for first time while it is retransmitted. However, in case, acknowledgment was lost, server may actually get same NFS command two times.

 

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Gateway for NFS

February 22nd, 2012 No comments

Gateway for the NFS Sharing application is used to make the gateway shares. Begin Gateway for the NFS Shares application from Services for the UNIX program group, and command line. So, from here you will make the gateway share, which is available to all the Windows clients like it were the local share from a gateway computer. Every gateway share makes use of the drive letter from gateway computer, and limiting number of the shares to maximum number of the free drive letters that are available on a gateway computer.

 

From command line, the Gateway for the NFS shares are all managed making use of gwshare.exe utility. For coming details on making use of the gwshare, see the type:

 

gwshare /?

 

Tip Gateway for the NFS shares are all limited by number of the available drive letters at a gateway server. However, in case, you need any additional shares beyond the number, you may use one or more gateway server for giving additional shares to distribute a load.

 

Server for the PCNFS

Server for the PCNFS gives PCNFSD support and you may enter all necessary information to make the users as well as groups using Services for the UNIX MMC, which may allow Server for the PCNFS to handle authentication of the NFS file resources for NFS clients.

 

Simplify the Network Administration

Services for the UNIX give some important tools to improve & simplify administration of the network and these tools will include:

 

  1. ActivePerl – Allows the existing & new scripts to take benefit of Windows Management Interface to automate the network administration tasks.

 

  1. Telnet Server – Allows character & script based administration of the Windows2000 & Windows NT servers from various clients.

 

  1. Telnet Client – Allows character & script based access or administration across various platforms.

 

  1. Microsoft Management Console Snapin –Allows the consistent & central management for all the SFU functionality.

 

 

Telnet Client

The SFU gives the character telnet client, which is faster & robust than default graphical client given by the Windows NT. In the Windows 2000, the Microsoft integrated the telnet client, and replacing old version. Telnet client that is supplied with the SFU goes totally beyond one in the Windows2000 for supporting both and console mode and stream mode, and gives for logging as well as additional configuration settings and commands, which make that more robust in the mixed environment.

 

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NFS Client Vulnerabilities

February 22nd, 2012 No comments

NFS clients might be in the danger from the NFS servers. For instance, the NFS mounted file system might have the setuid programs; the users on client will use these programs to get a root. The device entries on the NFS mounted partition are been considered to apply for the client’s devices, and not server’s devices. Someone with the account on NFS client & root permission on the NFS server will make use of this for getting the unlimited, read write access to data on a client.

 

Few NFS clients give the choices to mount that is used to disable the devices as well as setuid or setgid on the mounted file systems. In case, mount is not accessible to the users other than the root, or in case, it uses the options for the users other than the root, this can protect a client from server. In case, all these options are not accessible, even though just root will mount the file systems, you must consider mounting the NFS file system being equivalent in granting a server machine access to client.

 

The NFS clients might as well be vulnerable to the less obvious types of attack from the NFS servers. Mounting the file system is the privileged operation, thus NFS clients run as the root. The hostile server can exploit the buffer overflow errors in NFS client, and causing that to run the arbitrary programs. Generally, it is not transparent to user (that interferes with an ability to utilize whatever file system, which client tries to get), and it needs the attacker with high level of the control over server machine. In the traditional fixed server environments, it is not the major threat. Alternatively, use of the automounters that are been discussed in the later section, will make that the effective attack.

 

File Locking with the NFS

File locking enables one process to stop other processes to access the file in any specific ways. Often it is used to keep the multiple processes to write overlapping changes to the file, however it will as well get used for some other reasons (for example, it is advisable to keep some other processes from reading the file when it is changed). The NFS gives the voluntary file mechanism. So, by default, there are not any locks that are associated with the file, any process will do anything with that.

 

 

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Network File System (NFS)

February 20th, 2012 No comments

NFS protocol is made to allow the systems to have access files over the network on the remote system, conveniently like files were attached directly on disks. NFS protocol was made to get stateless for server implementation robustness and simplicity.

The stateless protocol is the one where every transaction is been handled separately; server will not have to keep the information regarding what clients already have done earlier. To be stateless allows the NFS server to reboot whereas clients are making the requests and, when it returns to the service, carry on serving files to the clients like nothing had ever happened.

 

This might appear like the fairly easy concept, however it is quite difficult in making the protocol stateless while it deals with the file access. Many important features of file systems are based inherently on the state. For example, to maintain the file locking needs keeping the track of what procedure has locked a file. The design decision had the major impact on the security as well as proliferation of the system administrator jokes that are based on kernel message the “NFS server not at all responding”.

 

Machines are NFS servers (and exporting the disks for an access by some other machines), the NFS clients (and accessing the disks exported by the NFS servers), and both. Almost each Unix implementation makes use of NFS as a primary method to share the files, or NFS client applications are accessible for other famous operating systems. (The NFS server applications for the nonUnix machines are rare.)

 

And 2 versions of the NFS are at present in the widespread use. The NFS version 2 is a protocol people are generally referring to while they mention this term NFS. It is generally run over the UDP (though specification allows any use of the TCP, most of the implementations don’t implement that). NFS version 3, often written as the NFSv3, is the newer version with many improvements, which includes support for the larger files, and each implementation allows to be run at TCP and UDP. From the safety standpoint, there is very little to distinguish between 2 versions, thus we make use of term NFS for applying to both the versions unless noted. NFS protocol is the straightforward RPC protocol, all the implementations and the versions make use of fixed port number (generally port 2049).

 

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File System – Organize Your Data Successfully!

February 4th, 2012 No comments

File system is a procedure of storing and organizing files in computer. Most importantly, it organizes files into a database for the storage, manipulation and retrieval by the computers operating system. File systems are used on hard disks or CD-ROMs to maintain the physical location of the files. Except this file systems provide access to data on a file server by acting as client for network protocol. The file system is accountable for organizing sectors into files and directories and keeps the record of which sectors belong to which file. It is can be used to represent and organize any data, whether it is stored or generated. File system usually used to secure storage location in the system memory. It has directories which associate file names with files. Now you can search more information about File system through the internet. You can also get several benefits by using file systems on your operating system.

As well referred to as the file system or else filesystem. System that the operating system and program makes use of organize & keep the track of files. Example, the hierarchical filesystem is one, which uses the directories for organizing the files in the tree structure. Though operating system gives own file management system, you may buy the separate file management. The systems also interact smoothly with operating system however give more and more features, like improved backup treatments & stricter file protection. Also, in computer, file system (at times written filesystem) is a way where files are been named & where they are been placed logically for the storage & retrieval. DOS, Windows, Macintosh, OS/2, as well as UNIX based systems have the file systems where files are been placed somewhere in the hierarchical structure. The file is been placed in the directory (the folder in the Windows) and subdirectory.

 

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File System – Allowing the System for Unlimited Accessibility!

February 3rd, 2012 No comments

File system is much essential part of any computer or operating system because it’s set all the program or application in proper manners. So, it is much easier for the users to design the correct file system for their computer for secure their data. In this regard, you have required following process to do so! Basically, file system is categorizing and storing all sorts of files in the separate database, so the user can easily access any file in quick time without any search. At the same way, it is also separate the web files, system files, application files in different data base for easy accessibility. File system is also responsible to downloading or installing any application files in your computer. However, file system is also permits the system for unlimited accessibility from the several storage devices at a same time as well as stores many attributes of file in it.

The file systems specify the conventions to name the files and these conventions also include maximum number of the characters in name that characters are used, and, in a few systems, how long this file name suffix is. The file system as well includes the format to specify path to the file through structure of the directories. At times term generally refers to part of the operating system and added on program, which supports the file system like defined. Thus, there will be 65535 clusters to every FAT 16 disk. What it means, is as the hard drive gets very huge, the cluster count stays same, thus the cluster size increases. However, do not think for one minute you may indefinitely increase size of every cluster. This will not happen and reason is each and every sector inside the group needs to get numbered. Every sector has index number, which is written inside the byte. Byte is eight bits and what it means is number needs to be very less than 2^8. And as way you decrement in the computers is going by the powers of two, it means you may store number 2^7, or else 128 sectors.

 

 

 

 

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File System – Access More Information!

February 3rd, 2012 No comments

Due to huge researches in technology filed, the researchers have been stated that file system is an important part of assortment operating systems. For more information, the file system is the best way to search the required files through any database. The procedure of file system is so simple to understand and users can locate their required files and documents easily. This sort of system is having numbers of benefits, so that it is the best option for those users who are facing problems for searching their required files in database. Also, this sort of system is keeping the file in tree structure through directory and subdirectory folders. Now, there are numbers of leading software companies available through which you can get your best solution to store your files and documents easily on your computer database. It’s the right time to get more information about this sort of system from the previous users.

The examples of add on file systems also include Network File System as well as Andrew file system. In specialized lingo of the storage professionals, file system is hardware that is used for the nonvolatile storage , software application, which controls hardware, as well as architecture of hardware & software. You can never figure out what they all meant. And this article can change that and by time I am done, you may know example what all these terms mean.

What is the File System?

First, let us now understand what the file system is. The file system is thought of as a way the computer goes about to manage files, which gets stored on the hard drive. The computer has plenty of files and in case, there were not any organized method to manage managing them, the system will be get slow, given it works. Take this mess, and multiply by thousand.

 

 

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File System – Foundation of Any System Setting!

February 2nd, 2012 No comments

File system is also known as the foundation to stand any sorts of business because it does manage all the system in proper manner. It is one of the vital parts of any operating system because it manages all the files in the system data base. However, these sorts of advantage never available in case of previous system setting but now every system have file system for proper storage. If you are requires creating your ideal filing systems, then you have required some easy steps to follow such as: firstly you will choose the right option from plastic filing crate and keen filing cabinet. However, it is always important for the user to choose double space according to their requirement to avoid the further problem. Now, due to development of advanced technology, creating file system is become much easier. In this regard, file system of Microsoft Windows are becoming much popular than other.

There are some other file systems, which go beyond meeting the basic requirements by giving the additional functionality, like encryption, compression, password or permissions, filestreams, and so on. Later on in the article, I may discuss a few of extra features that are in relation to the Windows NT’s NTFS. This is also understandable in case, you consider how much of stuff that you have already piled in the office, how much time that is wasted to find stuff, which is buried under lots of paper.

FAT In Detail

The section is technical in the nature than rest of article. Feel totally free to skip in case, you want. However, get warned you can miss a few some interesting tidbits regarding FAT you never knew. Thus, what is FAT, how do the file systems actually work? Answer is very simple actually. Space on the hard drive, at the most basic level, is been divided in the units named sectors. Every sector is around 512 bytes.

 

 

 

 

 

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File Systems – Essential Part of Operating System!

February 2nd, 2012 No comments

File systems are the vital part of operating system which has the capacity for long term storage. The mechanism for storing files and the directory structure are the two distinct part of file system. Now in the modern operating system it is possible for users to access same files simultaneously. File systems are also very necessary to control different forms of file in the operating system. It allows the system to access many different storage devices in the same way. The file system also stores a number of attributes for the files within it. All files have a name by which the user access it and most of the modern file system consist of three parts such as unique name, a period and extension. The file extension option enables the operating system to make a decision what to do with the file if somebody trying to open it.

It means every group will be made for handling one item and to illustrate point, think of following situation: File system chooses to divide people in groups of eight (we will get in how the number of selected later). All these eight people has the bag that will store stuff. File system hands first group the huge box of the pencils & says “store this.” Eight people begin to put pencils in the bags, and one fills up, and they move onto next and box of the pencils fills seven bags. File system tries handing group other small thing for putting in last 8th bag that is empty. However, group says “sorry, and we can just handle a thing. You already gave us one and file system says “ok, however you are wasting your space (1/8 = 0.125)” Group tells file system “sorry, we will not help it.” File system then moves on.

 

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File System – Required Proper Process!

February 1st, 2012 No comments

The file system of any computer’s may corrupt or damage due to several reasons such as: power failures, incorrect shorting down process of the computer or any sorts of hardware failures. If your file systems become damage in Ubuntu Linux, then the “fsck” is the right option for you to correct the damage. The improper installation of Ubuntu will make an only panel for root directory. While there is a single file system then it is always better for you to use the Ubuntu installation CD to boot the system that files system being never used. In this regard, you are requires some particular process such as: disclose the terminal window that available under the Accessories option of the main application window of your computer system. In this way, type the “mount” command to locate the file system on your computer system. After that Insert the Ubuntu setting up CD in your CD and DVD drive to solve the problem.

Now file system gives next group of eight, just single pencil for storing. Group stores that & refuses to take something and file system informs group they are wasting 100% of the storage space and there is not anything they will do. The stories might appear silly, however they do get point across that is as size of clusters increase, amount of the space that you waste can increase. It is also true that in case, you will make your files precisely same size as the cluster, you will have 0% of waste. However, this is not at all possible. Typical files are not big, as well as if cluster size gets very huge, then waste is quite alarming. Thus, now question gets how does my PC figure out size of every cluster? Answer is very simple, take size of the hard drive, as well as divide it by number of the clusters involved.

 

 

 

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