Two enterprise storage technologies that were fighting each other
for customers have now taken off the gloves and committed to
working together
For some time now, Network Attached Storage (NAS) and Storage
Area Networks (SAN) have been seen as alternative solutions to the
problem of storing enterprise-sized amounts of data.
SAN has been seen as a solution to issues such as bandwidth
problems and storage accessibility by providing a separate network
optimised for storage. NAS, on the other hand, works within the
existing LAN infrastructure in order to position storage where it
is needed.Those on the NAS side have claimed that a true SAN is a
long way from full implementation and expensive to implement, while
SAN supporters have said that NAS is not flexible or accessible
enough and takes up large amounts of precious network bandwidth.Now
it seems that the two sides have decided to put their differences
aside and, in a spirit of co-operation, have finally admitted that
NAS and SAN are not competing technologies, but complimentary ones.
A recent report from Bloor Research claims that the two are not
mutually exclusive, and "either or both can be used to solve the
specific issues than an organisation may face".Companies from both
sides of the storage debate are now saying that NAS technology on
the network could be relatively easily integrated into a SAN
environment, strengthening the storage capabilities of an
enterprise. Bringing the two technologies together could solve
problems that NAS or SAN would not be able to fix by
themselves.David Hill, analyst for Aberdeen Group, says: "Customers
are clamouring for storage system investments that will meet
today's needs but are also flexible enough to accommodate
tomorrow's storage capacity. Adding SAN capabilities to NAS does
this by creating a highly scalable system that can grow with the
customers increasing storage requirements. NAS and SAN technologies
each have their own advantages, making them an excellent complement
to one another by increasing overall storage capacity and speed at
an affordable price."Many companies have turned to Network Attached
Storage as a cheaper and more easily implemented way to backup and
share stored data. Once NAS is fully installed on a network it
would be difficult to justify a complete switch to SAN, even if the
technology and infrastructure would suit the business better. The
costs of a changeover would be huge, the logistics would be a
nightmare for larger companies, and it could well leave the
companies' data unprotected during the changeover. An intermediate
step allows for a much smoother changeover that does not render
most of the storage technology currently in use obsolete. It will
also pave the way for the integration of a full SAN solution,
whenever that time arrives.Now, vendors are finally coming together
to bring backup systems using both SAN and NAS to customers. Six
such companies have recently collaborated to introduce an
integrated NAS-SAN offering in what they say is a response to the
industry's need. Vixel, Legato Systems, Network Appliance, Quantum,
ATL, Spectra Logic and Veritas are claiming to be the first vendors
to be able to provide a complete NAS-SAN solution for data
protection.Arun Taneja, vice president, marketing for Vixel, says:
"At the end of the day, customers typically care most about
resolving their IT issues and enhancing their competitiveness, and
will deploy the appropriate technology to achieve that. Both SAN
and NAS have demonstrated their usefulness in different areas.
Those spearheading this solution have demonstrated how the
integration of the best from both SAN and NAS can ideally address a
real problem for the storage-centric IT customer."We can look at an
example of a heterogeneous network environment, such as a LAN
supporting NT and Unix servers. Data could be shared with both
operating systems via multi-protocol file servers and backed-up on
a tape drive connected to a dedicated backup server. This would
help fulfil basic storage requirements but could cause problems for
the network when implemented. LAN-based backup will require that
one or more storage servers be placed on the network. The regular
backup procedure will be carried out via the LAN using IP
protocols. Unfortunately, this then competes with end users, who
are accessing data through the network, for data bandwidth. The
sheer volume of data that a backup transfer can generate may create
severe bandwidth resource problems, even in the most sophisticated
switched network environments.A possible solution to this problem
is to schedule backups for times when the network is not in high
use, such as overnight, but even then the sheer volume of data
needing to be transferred may mean there is not enough time to do
so. Also, there are an increasing number of companies operating on
a 24-hour basis, and many companies, such as ISPs, cannot afford
any risk of downtime whatsoever.Another possible alternative is to
attach tape drives directly to the file servers via SCSI, therefore
taking the backup off the network. The problem with this option is
that it will require a tape drive for each and every file server,
increasing the cost of backup substantially as well as the
complexity of managing the drives and backup procedure. This also
means that because the stored data is spread around several
different tape drives across the network, it cannot easily be
retrieved or shared between the file servers.In this situation, it
could be of great advantage to implement the hybrid NAS-SAN
solution. A fibre channel SAN could be relatively easily integrated
with the storage already on the network in order to remove backup
traffic from the LAN. This would free up valuable bandwidth
resources and offer greater accessibility for retrieving lost
data.Instead of attaching tape drives to every file server or to a
backup server on the network, a Fibre Channel switch could be
introduced. File servers storing data could then be attached to the
switch directly via fibre, the switch in turn would then attach
directly to one or more tape backup drives. This ensures that the
data is stored in a single place making recovery much easier. Also,
because the drives are not placed in numerous places around the
network, manageability of the backup and recovery procedures is far
simpler and much more efficient. For larger networks, numerous file
servers can be integrated into the same SAN with mid-range tape
drive and larger tape libraries sharing the responsibility of data
access and archiving. Fibre Channel can also work over distances of
up to 10km and so can provide disaster recovery options for those
wishing to undertake that.The biggest advantage of all though is
that because all the tape drives have been removed from the network
and connected to the file servers via a Fibre Channel switch, the
Ethernet network is left uninterrupted and the bandwidth is freed
up to increase speeds for end users. This option, although not a
true SAN solution, does offer many of the benefits that SAN
professes to bring. In fact, it is widely recognised in the storage
community that the day of a fully functional, truly intelligent SAN
is still some way off. Some competing vendors continue to promote
proprietary solutions instead of championing the cause of a single
common standard for SAN technology. This situation is slowly
changing however. Many of the vendors are coming together to
provide multi-platform solutions, unfortunately, there are still
several different solutions out there from various vendors. Until
the industry pulls together to create offerings that comply with a
universal standard, the take-up of SAN technology by customers will
continue to ramp slowly.NAS too is still in the early adopter
stage, and has the price premium to go with it, but this should
change in the near future as the technology becomes more prevalent.
Companies that had previously held off buying NAS technology,
waiting for a truly intelligent and affordable SAN solution to
appear in the market can now reconsider their options.There are
also those enterprises that have gone ahead and installed NAS only
to find that the business has developed to a point where SAN would
be a more preferable technology. Previously, adopting NAS could
have blocked off an easy and affordable route to SAN. Now, whether
by accident or design, vendors have once again opened up the road
to SAN for those who have adopted, or are thinking of adopting NAS
technology.It is quite possible that if it were not for customer
demand, the two technologies would have remained as competitive
options. This may well have stifled both technologies progress into
the market, a situation all vendors in storage desperately want to
avoid, considering how unprofitable the lower end of the market has
become. Companies in both the NAS and SAN markets will no doubt
benefit from a blending of the two technologies, but hopefully the
real winner will be the customers, who should now be able to pick
what enterprise storage they want, when they want, and how they
want it. With the great amount of interest being taken by the major
vendors in these technologies, competitive pricing is also going to
offer better deals for potential buyers. As time goes on, more
players will enter the market and prices should fall even
further.NAS and SAN may initially seem like unusual bed partners,
but the technologies are not too far away from each other and are
getting closer every day. It's possible that this sort of hybrid
offerings will become standard in network enterprises, rather than
just part of a roadmap to SAN. But at least now, whatever suits
your business best, the option is at least there.
Paul
Grant