IP storage is not new to India Inc. NAS-and IP-based technologyhas
been widely deployed. That said, advances in this field have taken IP storage
to the big league where Fibre Channel once ruled. IP is set to take enterprise
storage by stormespecially in the SMB segment. by Anil Patrick R
Information must be available on the fly with reduced costs.
A cliché, but a truth that CIOs cannot ignore. This is where IP storage
is quietly stepping in, causing disquiet to its more popular fibre channel-based
IP-based storage has attained increased prominence at
the enterprise level because of the cost factor. It helps in total consolidation
of storage resources at a lower cost and centralises the storage architecture
Ajaz Munsiff, Regional Practice Leader, EMC Corporation
The developments in IP-based storage technology are of extreme
relevance to organisations worldwide, and increasingly so to the Indian enterprise.
This is because in the last few years, many Indian organisations realised the
need to shift from traditional DAS-based storage solutions to higher capability
options such as SANs. However, Fibre Channel (FC) SANs tend to elude these aspirants
because of high costs and issues such as complexity and interoperability.
IP-based storage emerges as a strong contender with its strengths on the cost,
capacity, scalability and manageability fronts. "Proponents of IP-based
storage claim that it offers a number of benefits over the FC alternative, and
will promote the widespread adoption of SANs that was predicted when they were
first introduced," says Ramanujam Komanduri, General Manager, Storage,
Sun Microsystems India.
This rise has been mainly due to advances in Ethernet and hard disk technology
that have helped IP storage to get maximum results from TCP/IP networks and
to gain a significant cost benefit. According to Ajaz Munsiff, Regional Practice
Leader, EMC Corporation, "IP-based storage has attained increased prominence
at the enterprise level because of the cost factor. It helps in total consolidation
of storage resources at a lower cost and centralises the storage architecture."
Before examining the latest in IP storage, we need to retrace the path travelled
by IP-based storage technology to the present.
The first real enterprise application of IP storage was the Network Attached
Storage (NAS) device. This provided enterprises with network storage that was
cost-effective and easy to implement/manage.
NAS was first developed close to late 1980s by the now defunct Auspex Systems.
The Auspex NAS was based on earlier file servers (IBM, Novell and Microsoft).
However, it was when Network Appliance bought over the patents from Auspex and
introduced their range of filers that NAS really hit the mainstream.
The main success of NAS has been that it is a low cost and convenient way to
organise, manage and access data stored on file systems such as the Network
File System (NFS) or Common Internet File System (CIFS). Best of all, the only
tasks required to operate a NAS are assigning an IP to the device, tweaking
the necessary settings and putting it on a TCP/IP network. This has resulted
in NAS vendors making a large profit on the enterprise storage market with the
Direct Attached Storage (DAS) market taking a major hit.
However, pure play NAS devices are capable of only file level data transfer,
which restricts their usage in applications such as Online Transaction Processing
(OLTP) requiring the faster block level data transfer capabilities available
only from SANs.
Storage management, consolidation and network utilisation also become issues
if there are too many NAS devices across the network. Because NAS devices use
the same LAN, network choke-ups can become routine during backups or during
peak data traffic.
iSCSI host connectivity to FC SANs offers significant
cost savings for both medium and large enterprises, and enables new strategies
including enterprise-wide tape backup
Tom Clark, Director, Solutions and Technologies, McData Corporation
FC SANs have their limitations as well, mainly on the cost,
complexity and interoperability fronts.
First, the entry-level costs of FC SANs are high. When organisations do a TCO/ROI
assessment, FC SANs are chosen only for crucial requirements and considering
Enterprises might not go in for fibre channel connectivity at all servers, because
every fibre or host adapter card can cost thousands of dollars. Most FC SANs
are monolithic in nature and future scaling up of SAN storage can be quite expensive.
While this might not be a major investment for large enterprises, it is definitely
not an affordable proposition for SMBs or enterprises requiring a standby DR
site or separate branch office SANs.
Complexity is the next inherent issue with FC SANs. Most FC SANs use proprietary
technology requiring training and experience for the storage administrator.
As many SAN users have found, acquiring this expertise is not easy. Further,
with the prevalent high attrition levels, it can be quite difficult to retain
good administrators. Complexity also causes flexibility issues.
FC SAN technology is not exactly known for its interoperability. The proprietary
nature is again the culprit. Different FC SAN vendors' products still do not
interoperate perfectly. Organisations are, therefore, compelled to stick to
the 'one vendor' policy for FC SANs.
Standardisation efforts by industry bodies such as the Storage Networking Industry
Association (SNIA) have helped FC SANs interoperate largely on the basic Fibre
Channel Protocol (FCP) and fabric levels. However, perfect interoperability
(especially for advanced features) is still remote.
Arise, the IP clan
So what's the best thing that has happened so far to IP Storage? Internet SCSI
(iSCSI), which, along with a couple of other new technologies, has brought capabilities
never before seen to IP storage solutions.
The iSCSI standard was developed by Internet Engineering Task Force (IETF) to
transmit SCSI data over a TCP/IP network. It was standardised in February 2003
and has developed as a much hyped/abused standard (depending on which vendor
you talked to) to its present strength.
iSCSI is capable of block level data transfer and has evolved as a worthy competitor
to FCP. However, the biggest benefit of iSCSI is that it uses TCP/IP networks
and can use existing network infrastructure and administrator skill sets to
offer low-cost connectivity for consolidation.
"iSCSI host connectivity to FC SANs offers significant cost savings for
both medium and large enterprises, and enables new strategies including enterprise-wide
tape backup," reveals Tom Clark, Director, Solutions and Technologies,
Most of the storage solutions available today, including FC SAN switches and
NAS devices with iSCSI interfaces, offer iSCSI support. "iSCSI extends
SAN benefits to stranded servers and storage. It also provides a cost-effective
IP storage infrastructure for entry-level SANs. In the case of NAS devices,
it extends NAS consolidation capabilities to include traditional block applications,"
says Ajaz Munsiff.
The potential of iSCSI is evident from the fact that the list of iSCSI-savvy
products includes those from some of the past vocal opponents of iSCSI. After
all, no vendor wants to be left behind! Therefore, they have also launched iSCSI-based
products or provide iSCSI support in their solutions. iSCSI has also spawned
a new generation of cost-effective, yet high-performance storage solutions.
One of the best iSCSI applications is the IP SAN. IP SANs employ iSCSI along
with Gigabit Ethernet (GbE) and cheaper high capacity technologies such as Serial
ATA (SATA) hard disk drives to obtain innovative high performance IP storage
solutions. According to Avijit Basu, Country Manager, HP StorageWorks Division,
"iSCSI's ease of use and extensive support from different operating systems
enable it to deliver everything that FCP can offer more cost effectively by
deploying managed IP SAN infrastructures."
With GbE becoming common in the enterprise, IP SANs have started competing with
1 Gbps FC SANs. To discover more about this innovative SAN development, read
the next story 'IP for the SAN'. Apart from iSCSI, other (earlier) developments
in IP storage include NAS-SAN gateways to connect NAS devices to SANs.
Going the long route
While iSCSI is charting new paths in corporate LAN, IP has also been active
on the SAN-SAN connectivity front. FCIP (Fibre Channel over IP) and iFCP (Internet
Fibre Channel Protocol) are two standards that can connect FC SANs using the
Optic fibre has limited maximum distance of deployment. This makes it essential
to find an alternative cost-effective technology if the SANs are further apart.
FCIP and iFCP attempt to bridge this gap by transmitting FCP data over the Internet.
These technologies can greatly boost the typical enterprise MAN/WAN's potential.
"Storage over long distance using iFCP (Internet Fibre Channel Protocol)
and FCIP (Fibre Channel over IP) is now widely deployed by large enterprises
and is making disaster recovery and remote storage consolidation affordable
for medium-size businesses," says Tom Clark.
FCIP-based products are available from Brocade and McData. On the iFCP products
front, McData is the only player dabbling with the technology at present. For
a detailed overview of FCIP and iFCP, refer to the story 'Save it for the WAN'.
Anil Patrick R can be reached at firstname.lastname@example.org