iSCSI: The Universal Storage Connection The Copenhagen Connection Basics and Application of Fibre Channel SAN, NAS, iSCSI,InfiniBand and FCoE. The iSCSI protocol enables universal access to storage devices and session may contain one or more TCP connections and provides recovery in the event. iSCSI. The Universal Storage Connection by John L. Hufferd Addison-Wesley, ISBN: X. John Hufferd is a known expert on the iSCSI.
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iSCSI make it possible to attach SCSI block storage Host system may connect to multiple SCSI buses. . portal7.info . Hufferd, J.L.: “ iSCSI: The Universal Storage Connection”, Addison-Wesley. ISCSI Universal Storage John Hufferd - Ebook download as PDF File .pdf), Text ISCSI: the universal storage connection / John L. iSCSI (Computer network. iSAN – A Storage Area Network made up of iSCSI connections. PDU - Protocol The iSCSI protocol enables universal access to storage devices and Storage.
The Universal Storage Connection is an informative overview and in-depth guide to the emerging iSCSI standard, the technology that enables data storage, access, and management over networks, intranets, and the Internet. The iSCSI protocol reduces the total cost of ownership of shared storage solutions and enables an organization to tie together disparate systems and data, including both server class systems and laptop and desktop systems. Written for network and data storage professionals, this comprehensive book introduces iSCSI and explores its growing role within the data storage industry. It describes each element of the technology in detail—from session establishment through error handling—and examines the relationship between iSCSI and the SCSI protocol from which it evolved. In addition, the book includes an explanation of the technologies that hardware vendors are implementing to permit direct memory placement of iSCSI messages without additional main processor involvement. A helpful icon appears throughout the book, mapping out appropriate reading tracks based on your technical level. Would you like to tell us about a lower price?
Kindle Edition File Size: Up to 5 simultaneous devices, per publisher limits Publisher: Addison-Wesley Professional; 1 edition 9 January Sold by: English ASIN: Enabled X-Ray: Not Enabled. No customer reviews. Share your thoughts with other customers.
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Verified download. However, if you dont have any background or even if u do starting directly with RFC can be really boring and may easily disorient you my personal experience. And this book will perfectly give that start. Just give yourself a start with this book and once you have gathered enough understanding of the protocol, switch to RFC for greater detail. I'm relatively new to storage networks. And even though there are other emerging technologies out there, this book was relevant for me, an easy read and continues to be a reference for ISCSI.
It's a good entry point for beginners to learn about iSCSI. This work is a thorough and insightful review of the iSCSI protocol by someone who has been a major contributor to the standard and knows the protocol parameters inside out.
I highly recommend this work to anyone who wants to understand the future direction of storage area networking. As stated in the book's title, iSCSI will be the universal connection for bringing storage into this synthesis. Many technical people found the IETF technical specifications hard to read, since it requires backgrounds from both the networking world and the storage world to fully understand them.
As one of the iSCSI authorities in the IETF, the author has done a very good job in describing the technologies and the ratioale of the specifications one step at a time in a very detailed and organized way. This makes them much easier to understand by the technical people from two different worlds. I fully appreciate John's efforts for creating such a great works that will be highly recommended for the time to come.
Go to site. Figure Small computer system interface SCSI. It defines how the SCSI device can be addressed, commanded to perform some operation, and give or take data to or from the host computing system. The operational commands are defined by a data structure called a command description block CDB. For example, a read command would have a CDB that contained an "opcode" defined by the protocol to mean, "read.
Generally, presenting the address on the hardware lines of the SCSI bus performs the addressing. This address technique calls out a particular SCSI device, which may then be subdivided into one or more logical units LUs.
An LU is an abstract concept that can represent various real objects such as tapes, printers, and scanners. Each LU is given an address. This is a simple number called the logical unit number LUN. Host processors can have many SCSI buses. The next thing to consider is what happens when many computers are in the same location. If there are numerous disks LUs for each system, this configuration creates a very large grouping of storage units.
Many installations group their servers and storage separately and put appropriate trained personnel in each area. These people are usually skilled in handling issues with either the computer system or the storage. One of the most prevalent issues for the storage specialist is supplying the proper amount of storage to the appropriate systems. As systems are actually used, the amount of storage originally planned for them can varyeither too much or too little.
Taking storage from one system's SCSI bus and moving it to another system's SCSI bus can be a major disruptive problem often requiring booting of the various systems.
Users want a pool of storage, which can be assigned in a nondisruptive manner to the servers as need requires. Another issue with the SCSI bus is that it has distance limitations varying from 1. The bus type has to be matched with the requirements of the host and the SCSI storage devices often called storage controllers , which seriously limits the amount of pooling a SCSI bus can provide. Further, many SCSI bus storage devices can have no more than one bus connected to them, and unless high-end storage devices are used, one generally has at most two SCSI bus connections per storage device.
In that case the storage devices have at most two different host systems that might share the various LUs within the SCSI devices. Two hosts sharing one storage control unit. Often the critical host systems want a primary and a secondary connection to the storage devices so that they have an alternate path in case of connection or bus failure. This results in additional problems for systems that want alternate paths to the storage and, at the same time, share the storage controllers with other hosts which might be part of a failover-capable cluster.
Often an installation requires a cluster made up of more than two hosts, and it uses a process called file sharing via a shared file system e. Pooled storage via SCSI connections.
The term "logical connection" is used because Fibre Channel FC components can be interconnected via hubs and switches. These interconnections make up a network and thus have many of the characteristics found in any network. This is being rectified, but the administrator of an IP network cannot now, and probably never will be able to, use the same network management tools on an FC network that are used on an IP network.
This requires duplicate training cost for the FC network administrator and the IP network administrator. These costs are in addition to the costs associated with the actual storage management duties of the storage administrator. I have had many storage customers request that storage be set up on an IP network, for which they have trained personnel. This request comes from the fact that FC networking has not been taught in colleges and universities.
This is a very expensive burden that must be borne by the customer of FC equipment. The more storage shipped that is FC connected, the more ruthless the demand for trained personnel.
Without universities providing trained graduates, companies will keep hiring people away from each other. Have versus want. Some people minimize this point and then go further and state that storage has different needs from other products located on a general IP network.
This is true; however, those needs are in addition to the management of the actual network fabric. Fibre Channel needed to invent general FC network fabric management as well as storage management.
It is the fabric management that people have been wishing were the same for both storage and the general IP network. Universities have not been training students because of a combination of factors: 1.
Fibre Channel does not yet replace any other curriculum item. Storage interconnect is seen as a specialty area. Few instructors have expertise in storage and storage interconnects.
Many university servers are not FC connected. The processors used by professors are not likely to be FC connected. That the main university servers are not Fibre Channel connected is a problem currently being addressed. However, the professors' local systems, which have significant budget issues, will probably be the last to be updated.
There is another solution to the problem of training, and that is the hiring of service companies that plan and install the FC networks. These companies also train customers to take over the day-to-day operations, but remain on call whenever needed to do fault isolation or to expand the network. This applies not only to the price of FC components, which are significantly more expensive than corresponding IP components, but also to operation and maintenance.
The cost of training personnel internally or hiring a service company to operate and maintain the FC network is a significant addition to the TCO. It is important to understand that storage networks have management needs that are not present in direct-attach SCSI.
The fact that Fibre Channel has suffered through the creation of many of these new storage management functions e. This applies not only to the company's collection of servers but also to their desktop and laptop systems.
The existing wiring infrastructure that most companies have is Category 5 Cat. It is expected that the customer will, over time, replace or upgrade his desktop system so that it has BaseT NICs. The resultant noise often sounds like sawing.
Likewise we can expect the desktop systems shipping in the coming year and beyond to be on the order of 1. The important point here is that iSCSI for desktops and laptops makes sense even if no special hardware is dedicated to its use.
This is a significant plus for iSCSI versus Fibre Channel, since Fibre Channel requires special hardware and is therefore unlikely to be deployed on desktop and laptop systems. Some people believe that the price of FC networks will fall to match that of IP networks.
I believe that will not occur for quite a while, since most FC sales are at the very high end of the market, where they are very entrenched. It therefore seems foolish for them to sacrifice their current profit margins, fighting for customers in the middle to low end of the market against iSCSI , where there are no trained personnel anyway.
I believe that FC prices will go down significantly when iSCSI become a threat at the market high end, which won't happen for some time. Thus, there is some impact from the additional work needed, even if supported by a chip.
A key future vendor-value-add will be how well a chip is able to parallel its processes and thus reduce the latency. This is not to say that the latency of iSCSI chips will be unacceptable.
In fact, it is believed that it will be small enough not to be noticeable in most normal operations. This will be significant for applications that require tape. An odd thing about tape is that almost everyone wants to be able to use it usually for backup but almost no one wants the tape library nearby. This permits customers to place their tape libraries in secure backup centers, such as "Iron Mountain.
At the bottom line, iSCSI is all about giving the customer the type of interconnect to storage that they have been requestinga network-connected storage configuration made up of components that the customer can download from many different places, whose download price is low, and whose operation is familiar to many people especially computer science graduates. They also get a network they can configure and operate via standard network management tools, thereby keeping the TCO low.
Customers do not have to invest in a totally new wiring installation, and they appreciate the fact that they can use Cat. They like the way that iSCSI can seamlessly operate, not only from server to local storage devices but also across campuses as well as remotely via WANs. These customers can use iSCSI to interconnect remote sites, which permits mirrored backup and recovery capability, as well as a remote connection to their tape libraries.
On top of all that, iSCSI will be operating on low-end systems and on high-end systems with performance as good as what FC networks can provide. If that is not enough, it also comes with built-in Internet Protocol security IPsec , which the customer can enable whenever using unsecured networks.
It is no wonder why customers, consultants, and vendors are singing the praises of iSCSI; it is a very compelling technology. It begins with the idea that a host can obtain its file storage remotely from the host system. The original SMB protocol ran only on small local networks. It was unable to operate seamlessly with the Internet and hence was generally limited to small LANs. A file server protocol places a file system "stub" on each host, which acts as a client of the target file server.
Like a normal file system, the file system stub is given control by the OS; however, it simply forwards the host's file system request to the remote file server for handling.