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File Services

File sharing was the original inspiration for networking. Novell originated with the need to share files between Unix, CPM, and DOS operating systems. The simplest solution was an independent file "server" that allowed file access from each of the three different "clients." The Novell NetWare file server was born, and the wave of connectivity that ensued was phenomenal. Early file services consisted of both client/server and peer-to-peer connections in a local area network (LAN) using the IPX protocol.

Today, the area of file services covers a vast collection of protocols, across multiple types of platforms, on different devices, distributed both locally and globally through VPNs and the Internet. In many enterprise environments, there is a need to share files based on different file formats, on different platforms, accessible from different clients with the need for seamless connectivity. Several open source solutions, including Samba, iFolder, and Linux, allow you to do just that.

What You Can Do

Linux and open source technologies provide you with the ability to accommodate a wide range of file services. Figure 3.3 shows what you can do.

Figure 3.3Figure 3.3 Linux technology allows you to share files across multiple server and client types.

The file services available include the following:

  • Access Linux file server from a Windows client—Samba is open source software that makes Linux or Unix platforms look like Microsoft Windows for file access and printing. It has been called "mediation" software because it allows Linux, Unix, and Windows servers to exist in the same network and be accessed by the same Windows clients without the clients ever detecting that the server is not Windows. This transparent access is handled through a protocol suite called the Common Internet File System (CIFS). CIFS is based on Server Message Block (SMB), an earlier version of the Microsoft file-sharing protocol. To a Windows workstation, a Linux server appears just like a Windows server with the same directory/file navigation and file manipulation capabilities.

  • Access a Windows server from a Linux client—Using Samba, the reverse is also possible, allowing Windows servers to appear as Linux or Unix hosts.

  • Access a Linux file server from a Macintosh client—Using Netatalk, a kernel-level implementation of the AppleTalk Protocol Suite (ATP), a Macintosh OS 9 or OS X client can retrieve, store, and manipulate files on a Linux server as if it were on another Macintosh machine.

  • Linux to Linux (Unix to Unix) file sharing—Network File System (NFS) is the native file-sharing protocol for both Linux and Unix. You can share files in any direction among these operating systems.

  • Store files in different formats—While Linux-based files can be accessed using different protocols, they can also be stored using different formats. Major supported formats include the following:

    • Reiser—ReiserFS is a journaling file system with optimized disk-space utilization, fast disk access, and quick access recovery. It is the default file system for SUSE Linux.

    • Ext 2/3—The ext3 file system is a journaling extension to the standard ext2 file system on Linux. Journaling reduces file-system-crash-recovery time and is widely used in high-availability sites with shared disks.

    • XFS—XFS is a high-performance journaling file system originally developed by SGI for use in its IRIX systems.

    • JFS—JFS is a full 64-bit file system that can support very large files and partitions. JFS provides a log-based, byte-level file system that is ideal for high-performance systems.

    Other file formats supported include Lustre, ISO9660 (CD-ROM), UDF (DVD/packet mode), EFS, CRAMFS (compressed RAM file system), ROMFS (small ROM file system), TMPFS (RAM disk file system), BFS (UnixWare boot file system), SYSV (SCP/Xenix/Coherent), UFS (BSD and derivatives), FAT/VFAT (Microsoft DOS and Windows 9x), NTFS (Microsoft Windows NT), HFS (Macintosh), HPFS (OS/2), QNX4, and Minix.

  • Upload and download files—Linux includes File Transfer Protocol (FTP) support, making it possible for authenticated users to upload, download, copy, delete, or rename files from any location on the Internet.

  • Synchronize files on different workstations—How often do you find yourself copying files to a floppy or emailing them to yourself so you can take your work home with you? Novell iFolder technology makes it possible for files to automatically follow you anywhere. Think of it as a synchronizing mechanism that automatically replicates changes made to a file on your workstation, first to a replica on the Internet, and then to any other workstation (notebook, home office, remote office, and so on) that you have specified. You make changes to files in your iFolder on your office PC and when you get home, those file changes are reflected in the updated files on your home computer.

Here's how iFolder works. A central iFolder server is configured at the data center on either Linux, NetWare, or Windows. This server includes a file repository and synchronization software. The iFolder synchronization capabilities are built using RSync, the open source utility that provides high-speed, incremental file transfer. On every workstation that is to be synchronized, an iFolder agent is installed and one or more synchronization directories are specified (MyDocuments, for example). Periodically or on demand, synchronization occurs, transferring file changes at the block level (minimal bandwidth required) on the workstation to the server and then out to the other workstations. The net effect is that a user can go from workstation to workstation, modifying or changing the same files without having to worry about copying or working from an outdated version.

Novell iFolder supports both Linux and Windows clients, making it possible for different workstations to be running different operating systems but still have access to the exact same files. You can also access iFolder files through the Internet using any standard web browser, giving you the ability to get to current files from the road, at a customer site, or from any device where you have access. A peer-to-peer version of Novell iFolder that allows users to share files in workgroup mode is being contributed to open source (see Figure 3.4).

Figure 3.4Figure 3.4 Novell iFolder keeps files on multiple workstations current all the time.

Other actions you can do include the following:

  • Access network files from a web browser—Using a standard web browser, you can access files that are stored on network Linux, Solaris, Windows, and NetWare file servers. Novell's NetStorage Gadget and Network File Gadgets work as a portal enhancement that can be included as part of any portal solution providing network file access. A user portal, for example, can be configured as a one-stop interface for access to mail, applications, collaboration tools, and file access.

  • The NetStorage Gadget takes mapped drives, home directories, and iFolder directories that are accessible based on a user's authentication and makes them available through a web portal interface. The Network File Gadget lets users access and upload files from any location (given proper authentication) using a specific network file provider gadget. File provider gadgets can be configured for NetWare UNC paths or eDirectory, CIFS file systems, or local file systems through Java. In effect, users never need a personal workstation to access personal network files.

  • Create storage area networks using the Internet—Storage area networks (SANs) are popular as storage repositories based on the Small Computer Systems Interface (SCSI) communications protocol, which uses low-level block storage access methods for high-speed access. SANs can be separate from individual workstations or servers and provide storage capabilities for entire projects, groups, or organizations. Common SAN technology uses expensive Fibre Channel hardware and the SCSI protocol. The Internet SCSI (iSCSI) protocol uses the same SCSI command set, but connects storage devices over less expensive Ethernet hardware using TCP/IP. This allows you to build high-speed, distributed SANs that are scalable, flexible, and easy to manage. Novell supports iSCSI on NetWare, and an open source version is available for Linux (see Figure 3.5).

  • Turn any Intel computer into Network-Attached Storage—Are your users adding video files or images to your network? If so, excess storage is most likely in sudden short supply. Novell provides a product called NetDevice NAS that turns any Intel-based computer into Network-Attached Storage (NAS) that is accessible by Windows, Linux, Unix, and web-based clients. NCP, CIFS, NFS, HTTP, HTTPS, AFP, and FTP protocols all have native access to the file system for transparent access to storage regardless of the client platform. NAS can be mapped by clients for access as they would any other network storage resource.

  • NetDevice NAS is "soft appliance" software that when installed, lays down a NAS appliance image, automatically configured to the hardware used. This creates a headless, lights-out NAS appliance that when connected to a network provides immediately accessible storage managed in conjunction with other network resources. Management is through Novell eDirectory, Telnet, or a web browser or can be console-based if a monitor and keyboard are attached.

    Figure 3.5Figure 3.5 iSCSI provides SAN capabilities across the Internet.

  • Supersize your file storage capabilities—Organizations with distributed and sometimes complex storage systems can benefit from the storage pooling and central management provided through Novell Storage Services (NSS). NSS is a storage and file system that provides an efficient way to use all of the space on your storage devices. NSS is best used with systems that require the capability to store and maintain large volumes and numerous files or large databases. NSS uses free storage space from multiple storage devices, combining it to create storage pools and logical volumes that are physically larger than the free space available on any single file server. NSS includes advanced storage technology that speeds the mounting of large volumes, mirrors and stripes data for redundancy, quickly recovers data after a file system crash, protects database systems with Transaction Tracking System (TTS), and more. NSS provides advanced file management capability and disk utilization for storage devices that are running on both NetWare and Linux platforms (see Figure 3.6).

  • Figure 3.6Figure 3.6 Novell Storage Services pools available storage to create logical volumes.

  • Map drives from your Linux workstation—Windows clients have long been able to map network drives using either Microsoft or Novell client software. This makes a drive appear as if it were local, usually with the next available driver letter (for example, F:). This same functionality is now possible with Linux clients as well. Workstations running Linux can map network drives that appear local to the user providing access to mass storage, SANs, or any other network storage.

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