iSCSI � What Does It Mean for Your Storage Network? Page 2
iSCSI Deployment Examples
Now, let's look at a few iSCSI deployment examples. The examples are as follows:
- Network Storage Services via iSCSI.
- Multiple Cards to Single iSCSI Router.
- iSCSI HBA and Fibre Channel Tape Backup.
Network Storage Services via iSCSI
Two iSCSI HBAs can be used in conjunction with standard Ethernet NICs through a Gigabit-capable switch connected to an iSCSI-capable Redundant Array of Inexpensive Disk (RAID) Array. This configuration is appropriate as either the next step in transitioning to an iSCSI-exclusive SAN or as an initial iSCSI SAN configuration.
Multiple Cards to Single iSCSI Router
Multiple HBAs in separate servers can be used in conjunction with a Gigabit capable switch connected to an iSCSI capable router with Fibre Channel ports. This is then connected directly to a native Fibre Channel RAID Array. This configuration is also appropriate as the next step in transitioning to an iSCSI front-end SAN with Fibre Channel storage devices.
iSCSI HBA and Fibre Channel Tape Backup
An iSCSI HBA can be used in conjunction with a Gigabit-capable switch connected to an iSCSI-capable router with Fibre Channel ports connected to a Fibre Channel tape drive. This configuration can be used as a means to perform backup and recovery, by using an existing Ethernet infrastructure.
Next, let's discuss what the availability of iSCSI will mean to customers who had considered storage networking too expensive. In other words, what are the advantages of iSCSI SANs?
As previously explained, iSCSI is an end-to-end protocol for transporting storage I/O block data over an IP network. The protocol is used on servers (initiators), storage devices (targets), and protocol transfer gateway devices. iSCSI uses standard Ethernet switches and routers to move the data from server to storage. It also enables IP and Ethernet infrastructure to be used for expanding access to SAN storage and extending SAN connectivity across any distance. The technology is based on SCSI commands used in storage traffic today and IP protocols for networking.
Leveraging the Best from Storage Networking
iSCSI builds on the two most widely used protocols from the storage and the networking worlds. From the storage side, iSCSI uses the SCSI command set, the core storage commands used throughout all storage configurations.
On the networking side, iSCSI uses IP and Ethernet, which are the basis for most enterprise networks, and uses in metropolitan and wide area networks is increasing as well. With almost 30 years of research, development and integration, IP networks provide the utmost in manageability, interoperability and cost-effectiveness.
10GbE Enabling iSCSI and Its AdvantagesAs the demand for bandwidth is increasing for storage and networking applications, Gigabit Ethernet technology provides the right path. However to make these applications mainstream, 10GbE is needed for the following reasons:
First of all, a 10 Gigabit Ethernet network will have the capabilities to provide solutions for unified storage and networking applications. With networking applications requiring gigabits of throughput and the terabits of storage transactions, existing gigabit networks will max out. However, 10GbE will be able to sustain lower latencies and high performance needed for these applications.
Second, with regards to interchangeability and Interoperability of equipment, the Fiber Channel model is not optimized for connectivity of multiple vendor devices. With 802.3 standards based products, Ethernet has continued to provide solutions that can connect systems for multiple vendors, thus allowing for a better cost model and a variety of vendors to chose from for the end user.
Third, would be the consolidation of the SAN and network attached storage (NAS) markets. The final reason why 10GbE is needed, is the ability to connect Fiber Channel SAN islands through IP. A link greater than the gigabit interfaces in the SAN islands is required.
So, with the preceding in mind, what would be the advantages of iSCSI SANs? The following advantages are as follows:
Building iSCSI SANs with 10GbE: A Data Center Approach
An iSCSI SAN is a perfect choice for a user interested in moving to networked storage. Using the same block level SCSI commands as direct attach storage, iSCSI provides compatibility with user applications such as file systems, databases, and web serving. Similarly, since iSCSI runs on ubiquitous and familiar IP networks, there is no need to learn a new networking infrastructure to realize SAN benefits. To build an iSCSI storage network in a data center, iSCSI host bus adapters can be used in servers, along with iSCSI storage devices and a combination of switches and routers.
An iSCSI SAN is an optimal choice for a user interested in moving to IP Storage. iSCSI is like one more application to the network protocol stack. So, iSCSI is not only compatible with the existing networking architecture, but also maintains the same block level SCSI commands. This capability allows the information technology (IT) staff to transition from the direct attached storage (DAS) model to the iSCSI SAN model. By adding the storage traffic to the existing network, the IT staff doesnt need any additional training to manage the networks for IP Storage.
In a typical data center, the servers updates/retrieves the data from the storage devices located remotely at gigabit speeds. Consolidated storage serves multiple servers at the same time. In the same environment, network traffic is processed at gigabit speeds. The IT staff has a challenging task to support the growing needs of storage and network requirements. Though gigabit networks are being deployed widely, it cannot solve all the problems. Storage networks have low latency and high bandwidth requirements.
iSCSI at 10 Gigabit Ethernet is the answer to these requirements. The 10GbE provides a smooth transition for the existing storage networking infrastructure to higher speeds. Applications like synchronous mirroring demand low latency, and file serving needs high bandwidth. By using a host bus adapter (HBA), which supports both the network protocols and the iSCSI protocols, both the SAN and NAS environments can be consolidated. The 10GbE networks facilitate the high bandwidth and low latency required in this environment, thereby resulting in improved application response time. This would consist of the following data center applications:
- Server and storage consolidation.
- Accelerated Backup Operations.
- Seamless Remote Site Access and Storage Outsourcing.
Server and Storage Consolidation
With a networked storage infrastructure, customers can link multiple storage devices to multiple servers. This allows for better resource utilization, ease of storage management, and simpler expansion of the storage infrastructure.
Accelerated Backup OperationsBackup operations previously restricted to operating across traditional IP LANs at the file level can now operate across IP Storage networks at the block level. This shift facilitates faster backup times, and provides customers the flexibility to use shared or dedicated IP networks for storage operations
Seamless Remote Site Access and Storage OutsourcingWith the storage network based on IP, customers can easily enable remote access to secondary sites across metropolitan or wide area IP networks. The remote sites can be used for off-site backup, clustering or mirroring replication. Additionally, customers can choose to link to storage service providers for storage outsourcing applications such as storage-on-demand.