STORAGE AREA NETWORK EXPLAINED PDF
Storage Networks Explained. Basics and Application of Fibre Channel SAN,. NAS, iSCSI, InfiniBand and FCoE,. Second Edition. Ulf Troppens, Wolfgang. This edition applies to the products in the IBM Storage Area Networks (SAN) portfolio. Note: Before using this information and the product it supports, read the . All you need to know about Storage Area Networks. The amount of data of an average company doubles every year. Thus, companies who.
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Storage Area Networks, such as IBM system engineers, IBM Business Partners, networks. It facilitates a common understanding of management data across. PDF | On Aug 15, , Vladimir V. Riabov and others published Storage Area model of the storage area network as a networked high-speed infras- .. Explained: Basics and Application of Fibre Channel SAN, NAS. PDF | On Dec 1, , Vladimir Riabov and others published Storage Area Networks Storage area network as a networked high-speed enterprise infrastructure (NT Storage networking essentials: A complete guide to understanding and.
The traditional archival process using optical disks and tapes is not optimized to recognize the content, so the same content could be archived several times. Additional costs are involved in offsite storage of media and media management. Tapes and optical media are also susceptible to wear and tear. CAS also meets the demand to improve data accessibility and to properly protect, dispose of, and ensure service-level agreements for archived data.
The features and benefits of CAS include the following: 1. Content authenticity: It assures the genuineness of stored content. This is achieved by generating a unique content address and automating the process of continuously checking and recalculating the content address for stored objects.
Content authenticity is assured because the address assigned to each piece of fixed content is as unique as a fingerprint. If the object fails validation, it is rebuilt from its mirrored copy. Content integrity: Refers to the assurance that the stored content has not been altered.
Use of hashing algorithm for content authenticity also ensures content integrity in CAS. If the fixed content is altered, CAS assigns a new address to the altered content, rather than overwrite the original fixed content, providing an audit trail and maintaining the fixed content in its original state.
Location independence: CAS uses a unique identifier that applications can leverage to retrieve data rather than a centralized directory, path names, or URLs. Using a content address to access fixed content makes the physical location of the data irrelevant to the application requesting the data. Therefore the location from which the data is accessed is transparent to the application. This yields complete content mobility to applications across locations. Single-instance storage SiS : The unique signature is used to guarantee the storage of only a single instance of an object.
This signature is derived from the binary representation of the object. At write time, the CAS system is polled to see if it already has an object with the same signature. If the object is already on the system, it is not stored, rather only a pointer to that object is created. SiS simplifies storage resource management tasks, especially when handling hundreds of terabytes of fixed content. Retention enforcement: Protecting and retaining data objects is a core requirement of an archive system.
CAS creates two immutable components: a data object and a meta-object for every object stored. For systems that support object-retention capabilities, the retention policies are enforced until the policies expire.
Storage area network
Record-level protection and disposition: All fixed content is stored in CAS once and is backed up with a protection scheme. The array is composed of one or more storage clusters.
Some CAS architectures provide an extra level of protection by replicating the content onto arrays located at a different location. The disposition of Dept. Technology independence: The CAS system interface is impervious to technology changes.
As long as the application server is able to map the original content address the data remains accessible. Although hardware changes are inevitable, the goal of CAS hardware vendors is to ensure compatibility across platforms. Random disk access in CAS enables fast record retrieval. It contains storage nodes and access nodes networked as a cluster by using a private LAN that is internal to it.
The internal LAN can be reconfigured automatically to detect the configuration changes such as the addition of storage or access nodes. These nodes run an operating system with special software that implements the features and functionality required in a CAS system. A node can be configured as a a storage node, b access node, or c dual-role node. They are sometimes referred to as back-end nodes. They establish connectivity through a private LAN to the storage nodes in the cluster.
The number of access nodes is determined by the amount of user required throughput from the cluster. This configuration is generally found in older installations of CAS. This node configuration is more typical than a pure access node configuration.
Integrity checking: It ensures that the content of the file matches the digital signature hashed output or CA. The integrity checks can be done on every read or by using a background process. If problems are identified in any of the objects the nodes automatically repair or regenerate the object.
Data protection and node resilience: This ensures that the content stored on the CAS system is available in the event of disk or node failure. Some CAS systems provide local replication or mirrors that copy a data object to another node in the same cluster. This decreases the total available capacity by 50 percent.
Parity protection is another way to protect CAS data. It uses less capacity to store data, but takes longer to regenerate the data if corrupted. Load balancing: Distributes data objects on multiple nodes to provide maximum throughput, availability, and capacity utilization. Scalability: Adding more nodes to the cluster without any interruption to data access and with minimum administrative overhead.
Self-diagnosis and repair: Automatically detects and repairs corrupted objects and alert the administrator of any potential problem. These failures can be at an object level or a node level. They are transparent to the users who access the archive. CAS systems can be configured to alert remote support teams who diagnose and make repairs remotely. Report generation and event notification: Provides on-demand reporting and event notification.
Fault tolerance: Ensures data availability if a component of the CAS system fails, through the use of redundant components and data protection schemes. Audit trails: Enable documentation of management activity and any access and disposition of data. Audit trails are mandated by compliance requirements. This process requires an understanding of the following CAS terminologies: 1. Application programming interface API : A high-level implementation of an interface that specifies the details of how clients can make service requests.
A typical check image archive can approach a size of TB. Chapter 10 Storage Virtualization As storage networking technology matures, larger and complex implementations are becoming more common.
The heterogeneous nature of storage infrastructures has further added to the complexity of managing and utilizing storage resources effectively.
Specialized technologies are required to meet stringent service level agreements and to provide an adaptable infrastructure with reduced cost of management. Virtualization is the technique of masking or abstracting physical resources, which simplifies the infrastructure and accommodates the increasing pace of business and technological changes.
It increases the utilization and capability of IT resources, such as servers, networks, or storage devices, beyond their physical limits. Virtualization simplifies resource management by pooling and sharing resources for maximum utilization and makes them appear as logical resources with enhanced capabilities. Since the beginning of the computer industry, memory has been and continues to be an expensive component of a host. It determines both the size and the number of applications that can run on a host.
With technological advancements, memory technology has changed and the cost of memory has decreased.
Virtual memory managers VMMs have evolved, enabling multiple applications to be hosted and processed simultaneously. In a virtual memory implementation, a memory address space is divided into contiguous blocks of fixed-size pages. A process known as paging saves inactive memory pages onto the disk and brings them back to physical memory when required.
This enables efficient use of available physical memory among different processes. The space used by VMMs on the disk is known as a swap file. A swap file also known as page file or swap space is a portion of the hard disk that functions like physical memory RAM to the operating system.
The operating system typically moves the least used data into the swap file so that RAM will be available for processes that are more active. Because the space allocated to the swap file is on the hard disk which is slower than the physical memory , access to this file is slower. VLANs make large networks more manageable by enabling a centralized configuration of devices located in physically diverse locations. Consider a company in which the users of a department are separated over a metropolitan area with their resources centrally located at one office.
In a typical network, each location has its own network connected to the others through routers. When network packets cross routers, latency influences network performance. With VLANs, users with similar access requirements can be grouped together into the same virtual network. This setup eliminates the need for network routing.
As a result, although users are physically located at disparate locations, they appear to be at the same location accessing resources locally. In addition to improving network performance, VLANs also provide enhanced security by isolating sensitive data from the other networks and by restricting access to the resources located within the networks. This technology improves storage area network SAN scalability, availability, and security.
Some of the features of VSAN are: Virtual machines provide a layer of abstraction between the operating system and the underlying hardware. Within a physical server, any number of virtual servers can be established; depending on hardware capabilities see Figure Each virtual server Dept. For example, the physical memory is shared between virtual servers but the address space is not. Individual virtual servers can be restarted, upgraded, or even crashed, without affecting the other virtual servers on the same physical machine.
Server virtualization addresses the issues that exist in a physical server environment. The virtualization layer, shown in Figure b , helps to overcome resource conflicts by isolating applications running on different operating systems on the same machine. In addition, server virtualization can dynamically move the underutilized hardware resources to a location where they are needed most, improving utilization of the underlying hardware resources.
This logical storage appears and behaves as physical storage directly connected to the host. Throughout the evolution of storage technology, some form of storage virtualization has been implemented. Figure illustrates a virtualized storage environment. At the top are four servers, each of which has one virtual volume assigned, which is currently in use by an application. These virtual volumes are mapped to the actual storage in the arrays, as shown at the bottom of the figure.
It specifies the types of virtualization: This requires a multilevel approach that characterizes virtualization at all three levels of the storage environment: An effective virtualization strategy distributes the intelligence across all three levels while centralizing the management and control functions. Data storage functions—such as RAID, caching, checksums, and hardware scanning—should remain on the array. Similarly, the host should control application-focused areas, such as clustering and application failover, and volume management of raw disks.
However, path redirection, path failover, data access, and distribution or load-balancing capabilities should be moved to the switch or the network. The third level of the storage virtualization taxonomy specifies the network level virtualization methodology, in-band or out-of-band. In an out-of-band implementation, the virtualized environment configuration is stored external to the data path.
The in-band implementation places the virtualization function in the data path, as shown in Figure b. It introduces a delay in the application response time because the data remains in the network for some time before being committed to the disk.
The storage virtualization solution must be capable of addressing issues such as scalability, functionality, manageability, and support. This environment may have several storage arrays that provide storage independently of each other. Each array is managed independently and meets application requirements in terms of IOPS and capacity.
The environment as a whole must now be analyzed. As a result, the infrastructure that is implemented both at a physical level and from a virtualization perspective must be able to adequately handle the workload, which may consist of different types of processing and traffic distribution.
Greater care must be exercised to ensure that storage devices are performing to meet the appropriate requirements. This includes local replication, extended-distance remote replication and the capability to provide application consistency across multiple volumes and arrays.
It should protect the existing investments in processes, skills, training, and human resources. They provide efficient and effective monitoring, reporting, planning, and provisioning services to the storage environment. The virtualized storage environment must be capable of meeting these challenges and must integrate with existing management tools to enable management of an end-to-end virtualized environment.
This environment may include multiple vendor technologies, such as switch and storage arrays, adding to complexity. However, supportability issues in a virtualized heterogeneous environment introduce challenges in coordination and compatibility of products and solutions from different manufacturers and vendors.
This facilitates the use of arrays from different vendors simultaneously, without any interoperability issues.
It also provides the advantage of non-disruptive data migration. No physical changes are required because the host still points to the same virtual targets on the virtualization device. Figure illustrates a NAS environment before and after the implementation of file-level virtualization. Each host knows exactly where its file-level resources are located.
An In-Depth Guide to the Differences Between SAN and NAS
Underutilized storage resources and capacity problems result because files are bound to a specific file server. Moving files across the environment is not easy and requires downtime for the file servers. It provides user or application independence from the location where the files are stored. This means that while the files are being moved, clients can access their files non-disruptively.
A global namespace can be used to map the logical path of a file to the physical path names. IT administrators manage storage area networks centrally. Storage arrays were initially all hard disk drive systems, but are increasingly populated with flash solid-state drives SSDs. This is an especially useful approach in small and midsize businesses that may not have the funds or expertise to support a Fibre Channel SAN.
Organizations use SANs for distributed applications that need fast local network performance. SANs improve the availability of applications through multiple data paths.
They can also improve application performance because they enable IT administrators to offload storage functions and segregate networks. Additionally, SANs help increase the effectiveness and use of storage because they enable administrators to consolidate resources and deliver tiered storage. SANs also improve data protection and security. Finally, SANs can span multiple sites, which helps companies with their business continuity strategies.
A SAN switch's only job is to move storage traffic. The switch checks the data packet and identifies its origin and destination. Then, the switch directs the packet to the right storage system. FC switches are meant to be used with high-performance networks. SAN switches can also be Ethernet based.Those Problems that are abstract and cannot solve on SAN infrastructure and application run on SAN can solve after understanding all the parameters.
The disposition of Dept. However, the goal of storage virtualization is to group multiple disk arrays from different vendors, scattered over a network, into a single storage device. At the top are four servers, each of which has one virtual volume assigned, which is currently in use by an application. It is a good idea to take a backup into the system, then it formalized and learned each every time.
Ultimately SAN networking and storage devices are available from many vendors. Some examples of fixed content asset include electronic documents, e-mail messages, Web pages, and digital media see Figure Patil, and S.