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Nas and san
- 1. An In-Depth Guideto the Differences Between SAN and NAS An Explanation of Storage Area Networks and Network Attached Storage NoorAzlinShahNawawe /EyeEm/GettyImages Internet & Network Basics Guides & Tutorials Installing & Upgrading Tips & Tricks Key Concepts What Are Bitcoins? by BradleyMitchell Updated February 22, 2018 203 Storage area networks (SANs) and network attached storage (NAS) both provide networked storage solutions. A NAS is a single storage device that operates on data files, while a SAN is a local network of multiple devices. The differences between NAS and SAN can be seen when comparing their cabling and how they're connected to the system, as well as how other devices communicate with them. However, the two are sometimes used together to form what's known as a unified SAN.
- 2. SAN vs. NASTechnology A NAS unit includes a dedicated hardware device that connects to a local area network, usually through an Ethernet connection. This NAS server authenticates clients and manages file operations in much the same manner as traditional file servers, through well-established network protocols. To reduce the costs that occur with traditional file servers, NAS devices generally run an embedded operating system on simplified hardware and lack peripherals like a monitor or keyboard and are instead managed through a browser tool. A SAN commonly utilizes Fibre Channel interconnects and connects a set of storage devices that are able to share data with one another. Important NAS and SAN Benefits The administrator of a home or small business network can connect one NAS device to a local area network. The device itself is a network node, much like computers and other TCP/IP devices, all of which maintain their own IP address and can effectively communicate with other networked devices. Given that the network attached storage device is attached to the network, all the other devices on that same network have easy access to it (given that proper permissions are set up). Because of their centralized nature, NAS devices offer an easy way for multiple users to access the same data, which is important in situations where users are collaborating on projects or utilizing the same company standards. Using a software program provided with the NAS hardware, a network administrator can set up automatic or manual backups and file copies between the NAS and all the other connected devices. Therefore, a NAS device is also useful for the opposite reason: to offload local data to the network storage device's much larger storage container. This is useful not only to ensure that users do not lose data, since the NAS can be backed up on a regular schedule regardless of the end-user's ability to back up, but also to give other network devices a place to keep large files, especially large files that are often shared among other network users.
- 3. Without a NAS,users have to find another (often slower) means to send data to other devices on the network, like over email or physically with flash drives. The NAS holds many gigabytes or terabytes of data, and administrators can add additional storage capacity to their network by installing additional NAS devices, although each NAS operates independently. Administrators of large enterprise networks may require many terabytes of centralized file storage or extremely high-speed file transfer operations. While installing an army of many NAS devices is not a practical option, administrators can instead install a SAN containing a high-performance disk array to provide the needed scalability and performance. However, SANs are not always physical. You can also create virtual SANs (VSANs) that are defined by a software program. Virtual SANs are easier to manage and offer better scalability since they're hardware independent and controlled entirely by easy-to-change software. SAN/NAS Convergence As internet technologies like TCP/IP and Ethernet proliferate worldwide, some SAN products are making the transition from Fibre Channel to the same IP-based approach NAS uses. Also, with the rapid improvements in disk storage technology, today's NAS devices now offer capacities and performance that once were only possible with SAN. These two industry factors have led to a partial convergence of NAS and SAN approaches to network storage, effectively creating high-speed, high-capacity, centrally located network devices. When SAN and NAS are joined together into one device in this way, it's sometimes referred to as "unified SAN," and it's often the case that the device is a NAS device that simply utilizes the same technology behind SAN. Network Attached Storage - NAS - Introduction to NAS Updated May 28, 2018
- 4. Several new methodsof utilizing computer networks for data storage have emerged in recent years. One popular approach, Network Attached Storage (NAS), allows homes and businesses to store and retrieve large amounts of data more affordably than ever before. Background of NAS Historically, floppy drives have been widely used to share data files, but today the storage needs of the average person far exceed the capacity of floppies. Businesses now maintain an increasingly large number of electronic documents and presentation sets including video clips. Home computer users, with the advent of MP3 music files and JPEG images scanned from photographs, likewise require greater and more convenient storage. Central file servers use basic client/server networking technologies to solve these data storage problems. In its simplest form, a file server consists of PC or workstation hardware running a network operating system (NOS) that supports controlled file sharing (such as Novell NetWare, UNIX® or Microsoft Windows). Hard drives installed in the server provide gigabytes of space per disk, and tape drives attached to these servers can extend this capacity even further. File servers boast a long track record of success, but many homes, workgroups and small businesses cannot justify dedicating a fully general-purpose computer to relatively simple data storage tasks. Enter NAS. What Is NAS? NAS challenges the traditional file server approach by creating systems designed specifically for data storage. Instead of starting with a general-purpose computer and configuring or removing features from that base, NAS designs begin with the bare- bones components necessary to support file transfers and add features "from the bottom up." Like traditional file servers, NAS follows a client/server design. A single hardware device, often called the NAS box or NAS head, acts as the interface between the NAS and network clients. These NAS devices require no monitor, keyboard or mouse. They generally run an embedded operating system rather than a full-featured NOS. One or
- 5. more disk (andpossibly tape) drives can be attached to many NAS systems to increase total capacity. Clients always connect to the NAS head, however, rather than to the individual storage devices. Clients generally access a NAS over an Ethernet connection. The NAS appears on the network as a single "node" that is the IP address of the head device. A NAS can store any data that appears in the form of files, such as email boxes, Web content, remote system backups, and so on. Overall, the uses of a NAS parallel those of traditional file servers. NAS systems strive for reliable operation and easy administration. They often include built-in features such as disk space quotas, secure authentication, or the automatic sending of email alerts should an error be detected. NAS Protocols Communication with a NAS head occurs over TCP/IP. More specifically, clients utilize any of several higher-level protocols (application or layer seven protocols in the OSI model) built on top of TCP/IP. The two application protocols most commonly associated with NAS are Sun Network File System (NFS) and Common Internet File System (CIFS). Both NFS and CIFS operate in client/server fashion. Both predate the modern NAS by many years; original work on these protocols took place in the 1980s. NFS was developed originally for sharing files between UNIX systems across a LAN. Support for NFS soon expanded to include non-UNIX systems; however, most NFS clients today are computers running some flavor of the UNIX operating system. The CIFS was formerly known as Server Message Block (SMB). SMB was developed by IBM and Microsoft to support file sharing in DOS. As the protocol became widely used in Windows, the name changed to CIFS. This same protocol appears today in UNIX systems as part of the Samba package. Many NAS systems also support Hypertext Transfer Protocol (HTTP). Clients can often download files in their Web browser from a NAS that supports HTTP. NAS systems also
- 6. commonly employ HTTPas an access protocol for Web-based administrative user interfaces. SAN Explained - Storage (or System) Area Networks The term SAN in computer networking most commonly refers to storage area networking but can also refer to system area networking. A storage area network is a type of local area network (LAN) designed to handle large data transfers and bulk storage of digital information. A SAN typically supports data storage, retrieval and replication on business networks using high-end servers, multiple disk arrays and interconnect technology. Storage networks work differently than mainstream client-server networks due to the special nature of their workloads. For example, home networks normally feature users browsing the Internet, which involve relatively small of amounts of data triggered at varying times, and can resend some requests if they happen to get lost. Storage networks, by comparison, must handle very large amounts of data generated in bulk requests and cannot afford to lose any of the data. A system area network is a cluster of high performance computers used for distributed processing applications requiring fast local network performance to support coordinated computation and output to external users. Fibre Channel vs. iSCSI The two dominant communication technologies for storage networks - Fibre Channel and Internet Small Computer Systems Interface (iSCSI) - have both been widely used in SANs and competed with each other for many years. Fibre Channel (FC) became the leading choice for SAN networking during the mid- 1990s. Traditional Fibre Channel networks contain special-purpose hardware called Fibre Channel switches that connect the storage to the SAN plus Fibre Channel HBAs (host bus adapters) that connect these switches to server computers. FC connections provide data rates between 1 Gbps and 16 Gbps.
- 7. iSCSI was createdas a lower cost, lower performance alternative to Fibre Channel and started growing in popularity during the mid-2000s. iSCSI works with Ethernet switches and physical connections instead of specialized hardware built specifically for storage workloads. It provides data rates of 10 Gbps and higher. iSCSI appeals especially to smaller businesses who usually do not have staff trained in the administration of Fibre Channel technology. On the other hand, organizations already experienced in Fibre Channel from history may not feel compelled to introduce iSCSI into their environment. An alternative form of FC called Fibre Channel over Ethernet (FCoE) was developed to lower the cost of FC solutions by eliminating the need to purchase HBA hardware. Not all Ethernet switches support FCoE, however. SAN Products Well-known makers of storage area network equipment include EMC, HP, IBM, and Brocade. In addition to FC switches and HBAs, vendors also sell storage bays and rack enclosures for the physical disk media. The cost of SAN equipment ranges from a few hundred up to thousands of dollars. SAN vs. NAS SAN technology is similar but distinct from network attached storage (NAS) technology. While SANs traditionally employ low-level network protocols for transferring disk blocks, a NAS device typically works over TCP/IP and can be integrated fairly easily into home computer networks.