IP Storage: Maximizing Investment

The term “IP Storage” is generally used to refer to a storage area

networking solution that uses standard Ethernet connectivity in some way. These

solutions typically fall into one of the two categories: Those that use an

Ethernet link to interconnect Fibre Channel SAN environments via gateways; and

those where a SAN is built using Gigabit Ethernet infrastructure instead of

Fibre Channel.

Consequently, IP, storage solutions typically extend and complement existing

SAN environments, or they provide affordable new SAN storage solutions in parts

of the IT infrastructure that are still dominated by direct-attached storage.

The benefits shared by all IP storage solutions derive from advantages

associated with standard Ethernet networking:

Using IP Storage to Interconnect SAN Islands

• Mature, well-understood technology with a long history of plug-and-play
  
  interoperability
• Low costs through commodity economics
• Strong roadmap to 40Gb and beyond
• Reliable, fault-to learn, with built-in quality of service
• Routable transport with no distance limitations
• Flexible provisioning and configuration
• A broad range of proven management tools
• Enormous knowledge and experience base-expertise in every IT organization

Taken all together, IP, storage solutions greatly broaden the options

available to IT executives to address the cost, availability, performance and

manageability issues caused by continual, data growth, and to accelerate their

transition from yesterday's direct-attached storage architecture to

tomorrow's networked Storage model.

Interconnecting Fibre Channel SANs



Two IP storage-bridging protocols are available to provide the basis for

interconnecting existing Fibre channel SAN environments. The use of IP networks

here is typically to overcome the distance limitations of Fibre Channel; to

provide lower cost solutions than using proprietary protocols over private fiber

links; and to enable ubiquitous remote data protection and disaster recovery

solutions.

FCIP is a TCP/IP-based tunneling protocol designed to transparently provide

point-to-point connections between geographically distributed Fibre Channel SANs

using FCIP gateways to connect to an IP network. It is particularly well suited

to provide connectivity to remote SANs for backup and restore, or remote data

replication applications.

iFCP is a TCP/IP-based protocol for interconnecting storage devices or Fibre

Channel SANs using an IP infrastructure. IFCP solutions consist of Fibre Channel

end-points connected to an IP network by means of iFCP gateways. It is

particularly well suited to providing the reliable transport of storage data

suited between separate SAN domains via TCP/IP LAN, MAN or W WAN infrastructure.

IP-Native SANs



In contrast, the iSCSI protocol enables the creation of complete SAN

solutions based on Gigabit Ethernet, instead of Fibre Channel, network

infrastructure. iSCSI is simply the combination of two very well-understood

technologies: SCSI block storage commands running over a TCP/IP transport. The

iSCSI protocol is an industry standard protocol (RFC 3720) created, maintained

and ratified by the Internet Engineering Task Force (IETF).

iSCSI is interesting as a SAN alternative to direct-attached storage in

environments where simplicity attached simplicity, flexibility,

price/performance, and availability of administrative staff are critical IT

decision factors, iSCSI SAN solutions (often called IPSANs) consist of iSCSI

initiators (software driver or adapter) in the application servers, connected to

iSCSI storage systems by means of standard Gigabit Ethernet switches and cables.

IP SANs are deployed for all the same reasons that Fibre Channel SANs are

typically deployed as an  alternative to direct attached storage.

According to IDC, the top reasons are:

Back: 46.0%



Storage consolidation: 40.0%


Satisfy on-going demands for additional capacity: 37.0%


Performance: 31.0%


Disaster recovery: 27.0%


New project or application deployment: 23.0%

Today backup and storage consolidation in the face of rapid, data growth are

the primary reasons for considering an IP SAN, followed by the intention to

implement an affordable disaster fordable recovery solution.

Where IP Storage Fits



The typical IT infrastructure of a large organization consists of a core

data center, usually running the, company's mission critical applications. Up

to 20% of the company's data assets are likely to be managed here. The rest

80% of the data is distributed among the company's regionals and departmental

data centers and across the various remote offices around the globe.

The core data center usually houses the company's largest servers, is

divided into production, and test and development environments, and is usually

considered home base for corporate IT. The penetration of networked storage, as

opposed to direct-attached storage, is likely to be up to 70% of the storage in

the core data center-the vast majority being in the form of Fibre Channel SAN

environments. Core data centers are most likely to have Fibre Channel savvy

storage specialists, as well as Ethernet savvy server administrators.

This core data center may be duplicated at a remote facility for disaster

recovery purposes, but the more likely scenario is that the disaster recovery

facility is one of the company's regional or departmental data centers.

Regional and departmental data centers usually look quite different than the

core data center. Servers here are likely to be smaller, and much more numerous.

The applications running in these environments may not be mission-critical, but

they are certainly business critical, and they are most likely to be driving

significant data growth. And that data growth causes a constant staffing and

asset management problem. The need for networked storage solutions is likely to

be most acute here, but the penetration of networked storage is only likely to

be around 30% -breaking down to a fairly even mix of network attached storage

solutions and small SAN environments. This type of data center is unlikely to

have either storage-focused or Fibre Channel savvy support staff.

Outside of the regional and departmental data centers, there will be a

significant number of remote offices. These offices are now likely to employ not

only desktop systems, but also a number of small servers, often running small

enterprise applications. IT support for remote offices is often a problem, and

data availability can be a real problem. Most companies are struggling with the

issues of integrating these offices into their corporate data protection and

management environment.

Interestingly, smaller organizations are likely to have a similar, multiple

data center environment, but the core data center will look much more like the

regional/departmental data center of a larger organization i.e, low networked

storage penetration, low Fibre Channel SAN penetration.

The IP storage bridging technologies provide the basis for bridging existing

Fibre Channel SAN environments, primarily for distance replication and disaster

recovery. Over the past two  years, these technologies have been adopted by

a wide range of organizations (from very large multinationals, to medium sized

regionals), usually as part of an asset consolidation, business continuance or

disaster recovery program. Customer case studies can be found on the websites of

many leading storage and network infrastructure vendors.

iSCSI has seen extremely broad adoption over the past three years (again in

both large and medium-sized organizations). Typically, iSCSI provides the basis

for SAN storage solutions (primary storage) in environments where it was not

considered to be feasible or cost effective.

IT infrastructure of a typical large enterprise

Today, iSCSI storage solutions are being deployed primarily in environments

dominated by mid-range and low-end servers. These classes of server are most

likely to be Intel-architecture servers running Windows, Novell NetWare or Linux

operating systems, though solutions for small RISC servers running Unix are also

emerging. The applications running here tend to be business-critical at the

departmental level, though you do see mission-critical applications for smaller

enterprises on these servers.

The most popular applications in these environments, therefore, are Microsoft

Exchange, Microsoft SQL fore, Server, and business applications running on top

of smaller Oracle or IBM DB2 databases. Messaging, Web, commerce, and some

technical applications (such as IBM Rational Clear Case) are also a good fit

with iSCSI environments. Finally, customers with home grown applications running

on smaller servers with internal or direct-attached storage are finding iSCSI a

great storage consolidation solution, since the migration to an IP SAN is

affordable and relatively painless. iSCSI is also a popular solution for

secondary storage in this environment, disk-based storage for regulated or

archive data.

Disk storage is often based on ATA drives and offers a cost per megabyte

comparable with small tape silos, with the advantage of much faster data

restore.

Low-end iSCSI solutions are also becoming popular as SAN solutions in remote

offices, provide the performance and availability benefits of centralized

storage. Solutions in this space often support file storage as in case of

SAN/NAS convergence. If these remote office solutions are linked back to primary

or secondary storage in the regional data center, the combination of remote

replication and regular pointing time copies (snapshots), not only eliminates

the backup in window and need for tape in the remote of office, but also

delivers extremely high data availability. Customer case studies of iSCSI being

used in producing IT environments are available on the websites of all the

leading IP storage vendors.

Over the past three years, IP Storage has rapidly entered the IT mainstream,

with products available from almost all the leading storage vendors, of offering

secure, reliable and flexible new SAN options to their customers. Today, IP

storage solutions are enabling organizations around the globe to maximize their

existing IT investments while deploying efficient networked data management

solutions.

David Dale



Industry Evangelist, NetApp, SNIA Board of Directors and Chair, IP

Storage Forum



www.ipstorage.org


vadmail@cybermedia.co.in