iSCSI Storage implementation explained through images

Here is another iSCSI implementation images to help you get a grasp of the topic

Running Storage subsystem with Serial Attached SCSI:Adaptec


An 8 channel SATA-II controller with PCI-X. Chip for XOR operations is clocked at 200 MHz. The chip on the previous four-channel model ran at just 66 MHz.


Internal hot swap bay for 4 SAS drives. A slimline CD/DVD-ROM can fit in the top of the case if only three 5.25" bays are available.


SAS cable is clearly visible at the back panel


Above images & article is courtesy of www.tgdaily.com/2005/03/18/cebit_2005/page4.html.

Software-based iSCSI Targets

* Linux/Netware/Solaris/NetBSD
- Openfiler - iSCSI (SAN) and NAS Linux distribution - An open source iSCSI target implementation for Linux
- Intel-iSCSI (Intel) - The earliest open source release of iSCSI (March 2001). The distribution includes initiator and target code for Linux 2.4 and 2.6 and support for Object-based Storage Devices (OSD). External Link
- iSCSI Enterprise Target - An open source iSCSI target implementation for Linux
- Linux - iSCSI target product offerings from 3rd party vendors for various flavors of Linux [1] [2] MayaStor iSCSI [3]
- NetBSD target HOWTO
- NetWare 6.5 includes an iSCSI target module
- Solaris iSCSI Target - iSCSI target package bundled with Solaris.
- DataCore Software's SANsymphony [4] storage virtualization software for Windows 2000/XP/2003
- String Bean Software's WinTarget [5] - acquired by Microsoft and renamed to Microsoft iSCSI Target, now offered as an option pack from OEM's for Windows Storage Server 2003 R2 [6]
- Rocket Division Software StarWind iSCSI Target for Windows 2000/XP/2003
- FalconStor - iSCSI Storage Server [7] for Windows 2003 and Windows 2003 Storage Server
- DataCore SANmelody [8] & SANmelody Lite [9] iSCSI target and disk server software for Windows 2000/XP/2003
- Nimbus Data Systems - MySAN iSCSI Server [10] Free iSCSI target for Windows 2003 Server
- Virtual Infrastructure Foundation kit iSCSI target and thin provisioning software for Windows systems

* Other
- Open-E iSCSI-R3 - iSCSI storage software is pre-installed on a USB-DOM
- Open-E DSS - data storage software (NAS + iSCSI ) on pre-installed USB-DOM
- Software target implementations are also available or included on storage devices from vendors such as EMC, Equallogic, Reldata, LeftHand Networks, Network Appliance, Stonefly and StorageConnections.Net.
- Wasabi Systems Storage Builder for IP-SAN comes pre-installed on a bootable Compact Flash IDE disk and runs on standard hardware platforms.

iSCSI Storage Solutions to solve Business Requirements

Continuing the previous post on iSCSI . This is an important topic for Storage professionals as its going to be the next major trend.

Adaptec iSCSI initiator


iSCSI host bus adapters (HBAs) are network interface controllers that incorporate a TCP Offload Engine with onboard iSCSI processing. iSCSI HBAs are usually abstracted purely as SCSI controllers by the operating system driver system. In this case, the HBA is not a part of the system network stack. Recently there has been considerable effort in providing standard vendor-independent iSCSI management facilities via operating system driver interfaces. These standard interfaces also work with software initiators.

Qlogic iSCSI HBA

Since iSCSI HBAs offload considerable processing in the iSCSI stack, interrupt generation is less than comparable software initiator setups. Applications leaving few spare CPU cycles should benefit from the use of a dedicated HBA.

HP Fires a Bullet through its Storage array for a Stress Test


iSCSI HBAs have the advantage of including PCI option ROMS to allow booting from iSCSI targets. Alternative iSCSI boot methods with software initiators would require substantial work.

The following vendors have developed iSCSI HBAs:

* Adaptec (Product is discontinued.)
* Alacritech
* Intel (Product is discontinued.)
* Qlogic
* Silverback Systems External Link

Targets
Most industry focus has been placed on creating iSCSI disk targets though iSCSI tape and medium changer targets are popular as well. So far, physical devices have not featured native iSCSI interfaces on a component level. Instead, devices with SCSI Parallel Interface or Fibre Channel interfaces are bridged by using iSCSI target software, external bridges, or controllers internal to the device enclosure.

Alternatively, disk and tape targets can be virtualizations. Rather than representing an actual physical device, an emulated virtual device is presented. The underlying implementation can deviate drastically from the presented target as is done with Virtual Tape Library (VTL) solutions. VTLs use disk storage for storing data written to virtual tapes. As with actual physical devices, virtual targets are presented by using iSCSI target software, external bridges, or controllers internal to the device enclosure.

Addressing and Name formats
iSCSI provides two name formats for different types of naming authorities:

* iSCSI Qualified Name (IQN), Format: iqn.yyyy-mm.{reversed domain name} (e.g. iqn.2001-04.com.acme:storage.tape.sys1.xyz)
* Extended Unique Identifier (EUI), Format: eui.{EUI-64 bit address} (e.g. eui.02004567A425678D)

In the case of IQN the address is qualified by a date (yyyy-mm) since a domain name can expire or be acquired by another entity. EUI is provided by the IEEE Registration authority in accordance with EUI-64 standard.

Each target is defined by three or four fields:
HostNameOrAddress PortNumber iSCSIName CHAPSecret (optional)

Example:
iscsi.fake.com 3260 iqn.2003-01.com.ibm:00.fcd0ab21.shark128 "123ismysecretpassword"

What is iSCSI Storage Solution Is it one of the Top Storage Technologies

Email roger.smithson@gmail.com for a FREE SAN STUDENT GUIDE pdf file


If you aspire to be a professional in Storage IT company its a MUST to know FC & iSCSI. There was a previous post about FC & below is a brief on iSCSI .
As per Wikipedia's definition Internet SCSI (iSCSI) is a network protocol standard, officially ratified on 2003-02-11 by the Internet Engineering Task Force, that allows the use of the SCSI protocol over TCP/IP networks. iSCSI is a transport layer protocol in the SCSI-3 specifications framework. Other protocols in the transport layer include SCSI Parallel Interface and Fibre Channel.
The iSCSI (pronounced eye-skuzzy) protocol uses TCP/IP for its data transfer. Unlike other network storage protocols, such as Fibre Channel (which is the foundation of most SANs), it requires only the simple and ubiquitous Ethernet interface (or any other TCP/IP-capable network) to operate. This enables low-cost centralization of storage without all of the usual expense and incompatibility normally associated with Fibre Channel storage area networks.

Acceptance of iSCSI in corporate production environments has accelerated now that Gigabit Ethernet is common. Building iSCSI-based Storage Area Networks (SAN) has become a less costly but worthy alternative to creating Fibre Channel-based SANs.

iSCSI terminology and how iSCSI can be used by an OS

An iSCSI initiator, in client/server terminology, is akin to a client device that connects to some service offered by the server (in this case an iSCSI target). An iSCSI target is akin to a server, in that it provides block level access to its storage media (usually a hard drive, but can be other types of SCSI devices if the iSCSI target software supports them.) The primary difference between a regular client/server system and an iSCSI initiator/target system is that while many clients can be simultaneously served by a single server (many-to-one), only one iSCSI initiator can talk to a given iSCSI target at a time (one-to-one).

iSCSI can be used to give an OS block-level access to a remote device (one attached to another computer likely on the same LAN). Depending on the types of devices supported by the iSCSI target, this block-level access can be used to build RAID volumes using remote disks, or to connect and use remote DVD/CD-writers and scanners, or to simply access additional storage space. iSCSI devices are not shared by iSCSI amongst multiple computers at the same time; instead the OS in control of the iSCSI device is responsible for controlling remote access to the device. The initiator and the OS that it is running on will determine how the iSCSI device appears, and whether it is a /dev entry or gets a drive letter or something else.
Source : Weblinkhttp://en.wikipedia.org/wiki/Iscsi


ESG reports that it has identified 2500 iSCSI SAN deployments, and expects deployments to increase substantially in 2005. According to another ESG study of 130 SMB end users, 17% have already deployed an iSCSI SAN, and another 42% are planning to deploy iSCSI SANs by mid 2006. Spectra Logic’s interactions with customers support ESG’s expectations, given the increasing rate of Spectra Logic’s iSCSI products sales, the increasing support of iSCSI drivers/initiators by major operating systems, and the major vendor commitments to the technology.

Microsoft continues to be a major force behind iSCSI, pushing to make iSCSI SAN deployment even easier and even more “risk-free” to the masses. Considering that most of the growth within the storage market will come from small to medium businesses–environments heavily dominated by Windows and Linux–other major storage vendors are certainly enticed to work with MS to make “iSCSI SANs for the masses” a reality. Economics of scale make their decision and direction an easy one, further eased in that iSCSI is already supported in most operating systems.

Source :Weblink from spectralogic.com

A Video Tutorial explaining different Computer Interfaces like PCI,SCSI etc


Video of Kids having fun taking apart a SCSI drive