SAN Features

Today SANs come with features that can really help your enterprise manage your data and your virtual machines.

iSCSI is a type of SAN that uses industry technologies such as Ethernet and Ethernet NICs for transport and an interface. So far iSCSI has proven to be a great lower-cost solution to the Fibre Channel SAN solutions that are available. If, for instance, you are building your virtualization environment on servers that are worth U.S. $4,000 and you want to connect them to your Fibre Channel SAN, you will have to purchase Fibre Channel adapter cards that are compatible with your SAN. Each one of the Fibre Channel cards you implement into your server can range from $1,000 to $2,000 each. That can really start to be an additional cost if you are building out one or more 16-node clusters.

Now we’re sure some of you reading this are saying, “Well yeah, but I’ve already implemented my Fibre Channel architecture. Now you want me to implement another infrastructure just for this?”

Well, no, that’s not the case. What we’re saying is that if you don’t already have an infrastructure in place, iSCSI would be a great technology for you to research. One other consideration you will want to keep in mind when you are determining whether initiator comes into play. The iSCSI initiator can, like the target, be software or hardware. Most implementations that we are seeing today are running free software iSCSI initiators that come with most operating systems. Depending on the servers that you are buying, you can also buy hardware iSCSI initiators. If you find that a software initiator isn’t giving you the performance that you need, you can purchase hardware initiator cards that also have TCP/IP offload engines to help speed up the traffic.

Direct Attached Storage
Direct attached storage (DAS) is a storage array that is directly connected, rather than connected via a storage network. The DAS is generally used for one or more enclosures that hold multiple disks in a RAID configuration.

DAS, as the name suggests, is directly connected to a machine, and is not directly accessible to other devices. For an individual computer user, the hard drive is the most common form of DAS. In an enterprise, providing storage that can be shared by multiple computers tends to be more efficient and easier to manage.

The main protocols used in DAS are ATA, SATA, SCSI, SAS, and Fibre Channel. A typical DAS system is made of one or more enclosures holding storage devices such as hard disk drives, and one or more controllers. The interface with the server or the workstation is made through a host bus adapter.

Network attached storage (NAS) is a hardware device that contains multiple disks in a
RAID configuration that purely provides a file system for data storage and tools to manage that data and access. An NAS device is very similar to a traditional file server, but the operating system has been stripped down and optimized for file serving to a heterogeneous environment. To serve files to both UNIX/Linux and Microsoft Windows, most NAS devices support NFS and the SMB/CIFS protocols.

NAS is set up with its own network address. By removing storage access and its management from the server, both application programming and files can be served faster, because they are not competing for the same processor resources. NAS is connected to the LAN and assigned an IP address. File requests are mapped by the main server to the NAS server.

NAS can be a step toward and included as part of a more sophisticated SAN. NAS software can usually handle a number of network protocols, including Microsoft’s Internetwork Packet Exchange and NetBEUI and Novell’s Netware configuration.

Source of Information : Microsoft Virtualization with Hyper V


Subscribe to Developer Techno ?
Enter your email address:

Delivered by FeedBurner