Supermarket
Tesco is considering deploying mainframes to reduce its carbon
footprint. They may well be
greener than data centres full of PC servers, but will IT
directors start buying mainframes again to improve data centre
energy efficiency?
IBM has worked hard over the past 12 months to sell the green
potential of its mainframes. The argument is simple enough.
Mainframes can do more work per kilowatt of electricity consumed
compared to clusters of Unix and Windows servers in a data centre.
While a single mainframe consumes more electricity than a single
blade server, hundreds of blades are needed to achieve the
equivalent computational throughput of a mainframe.
Research from analyst Robert
Frances Group backs up IBM's claims. Its calculations for a
large US retailer found that a monthly power bill of $30,165 for
UNIX servers could be reduced to $905 for a z-series mainframe,
representing over $350,000 in power costs annually.
Businesses assessing the mainframe need to buy
IBM's z-series
hardware equipped with a processor called IFL
(Integrated
facility for Linux), which runs Linux applications. The IFL
processors are priced at $125,000 per unit, but Phil Payne, analyst
at Isham Research, says users should be able to negotiate a price
of about $30,000 each.
For existing z series users, this additional fee may be a
worthwhile investment, allowing them to gain power efficiencies by
moving Linux applications onto the IFL on the z-series
mainframe.
While the numbers make sense on paper, few companies are
following Tesco in looking at the viability of bringing back
mainframe computing to reduce their carbon footprint.
Rakesh Kumar, vice-president at analyst
Gartner, says, "I think it would be a
brave user who would consider replacing Unix servers with
mainframes running Linux." However, for businesses already running
mainframes, Kumar recommends IT directors negotiate a good price
for the IFL and software licence charges. If the price is right, he
says, "It may well make sense to put the new applications on the
mainframe, otherwise, stick to PC servers," he says.
IBM has seen growth in demand for mainframe applications. ""We
are not seeing much interest in Europe, but we are getting new
customers in China and India for the z-series." Douglas Nielson, a
systems analyst at IBM, says Linux on the mainframe is quite
mature. "Linux is a big driver for mainframe growth. 20% of new
mainframe capacity is for Linux workloads." He says many businesses
already have the IFL processor to allow them to run Linux.
So if businesses already run z-series hardware and have licensed
the IFL Linux processors, they could look at moving some Linux
applications onto the mainframe. Clearly, the mainframe is not
going to suit everyone, and only certain applications can benefit
from being run on Linux on a z-series. But, users could see
significantly lower data centre power bills, where it is
deployed.