Fibre Channel
Fibre channel was the first technology that allowed the physical disk drives to be remote from the servers and yet allowed the servers to believe that the disks were directly attached.
Fibre Channel Advantages
- All storage is now managed centrally
- The storage is served up to the servers via fibre channel
- Fibre channel SAN’s can run at 4Gbits per second with 8Gb/s due in 2008
- Storage can be added on demand with no server downtime
Fibre Channel Disadvantages
- Requires an in depth understanding of LUN mapping, World Wide Names, LUN masking, Storage Virtualisation, Storage management etc.
- All servers now require Fibre Channel cards, Fibre Channel Switches, Fibre Channel Storage Arrays, and Separate Fibre Channel Network!
- Fibre Channels are expensive to install, maintain and manage.
iSCSI The alternative to Fibre Channel?
Whilst a FC-SAN provides centralised storage and performance it comes at a high price. An alternative to Fibre Channel is iSCSI. iSCSI has all of the functionality of Fibre Channel and some major advantages as well.
iSCSI is a network storage protocol that encompasses block level SCSI data in a TCP/IP frame, thus allowing servers to access storage resources over an existing IP infrastructure. As the storage is physically stored remote from the servers, the applications treat the disk as if it were directly attached.
SCSI and Ethernet technologies have been around for more than 20 years and are fully understood.
iSCSI is a cost effective way to build SAN’s at much lower cost point, giving users greater consolidation in their environment.
The iSCSI storage protocol is supported by 99% of the storage vendors and endorsed by Microsoft, Intel, IBM and Cisco.
- As iSCSI uses IP as a block level transport for disk drives
- We can utilise your existing Gigabit network for serving up disk space on demand.
- Save money by buying servers with mirrored operating system disks
- Should a server fail or need upgrading then the storage can be mounted on another server and simply/instantly restored
- Microsoft fully endorses the iSCSI protocol for Exchange and SQL. The new Microsoft OS Vista and Windows Server 2008 both fully support the iSCSI protocol
- One person can administer and control all you storage requirements from a single system and allocate disk on demand
- Cut down on Backup Software Licensing costs as all you need to do is Snapshot or Mirror the information to another server and backup just one server!
- No massive storage investment is needed
- Reduced maintenance costs and more reliable servers
- Utilises all your disk storage and takes the guess work out of how much is required
- Reduces management costs as additional disk space can be easily added to the servers
iSCSI is an OPEN architecture that enables an optimised and cost effective TCO (Total Cost of Ownership) to be achieved and your TCO is protected for the future, whereas Fibre Channel is a TIED architecture that can only see an increase in TCO in the future.
NAS - Network Attached Storage
Network Attached Storage separates the application server from the storage. This increases overall system performance by allowing the servers to perform application requests and the NAS to serve files or run applications.
As the name suggests Network Attached Storage allows disk-based storage to connect directly on a network using a 10/100Mbit or Gigabit Ethernet connection, many now also feature dual Gigabit connectivity. It is a fully self-contained file server that can be used to serve files or run applications. A wide variety of networking protocols can also be supported TCP/IP, IPX, NetBEUI, Appletalk, NFS v3, HTTP 1.1, FTP this allows a wide variety of operating systems access to the NAS Storage.
The disk capacities range from a single spindle disk of 80GB all the way up to a multi-terabyte disk solution.
All NAS Servers use an operating system; this operating system is typically Windows 2003 Storage Server or Linux. Once the NAS is connected to the network the NAS Server becomes a virtual OS server mimicking a Windows 2003, MAC, Unix or Linux server etc. One of the major benefits of using Network Attached Storage is there are no software licences payable.
You can now easily create users shares, integrate it into Microsoft Active Directory or create drive letters on the users desktop.
A NAS server has all the components of a traditional server but has no keyboard, monitor and mouse connected. The NAS servers have hard disks, processors, motherboards, memory, SCSI controllers, power supplies, fans and networking for connectivity. Management of the NAS Server is via a web browser or Windows Terminal Services. From this you can configure and monitor all the functionality the NAS Server offers. The typical configuration time for a NAS device is about 15 minutes from connection.
A main advantage of NAS is no software licensing costs are applicable. Many also have multiple levels of redundancy.
