Dow Chemical is showing that predictions made as recently as early
this year that mission-critical databases at big companies would
never find their way to iSCSI storage may have been ill-advised.
In a presentation at the Storage Networking World (SNW)
conference, Steve Remsing, senior systems administrator for Dow
Chemical, detailed his company's painstaking test process for
Oracle 10g R2 on different combinations of Windows, Linux, Fibre
Channel and iSCSI. Remsing said in the presentation that Dow
Chemical now has plans to push multiple Oracle databases of under 1
terabyte (TB) onto Network Appliance Inc.'s (NetApp) FAS270c iSCSI
array. He didn't say exactly how many or what specifically they
were used for, other than to say they were for data collection and
retention for research.
"We've shown we could get it to work," Remsing said. As for the
chief reason for going with iSCSI over Fibre Channel, Remsing gave
the same answer as the little guys: cost. He said he couldn't get
into how much the company saved by moving from Fibre Channel to
iSCSI, but said he was intrigued by the idea of using regular
server network interface cards (NICs) and standard Cisco Gigabit
Ethernet (GigE) switches rather than specialized Fibre Channel
equipment.
"ISCSI has matured," Remsing said. "Vendors have been through
version 1.0 of their products, whether it's initiators or storage,
and it's ready to handle these kinds of things."
Remsing said he had no worries about the reliability of iSCSI,
but that he would keep an eye on performance. "We will look at
adding TCP/IP offload (TOE) cards or moving some applications to
Fibre Channel if that becomes necessary," he said.
"We believe that more and more companies will use iSCSI for
mission-critical applications as a natural progression in its
adoption cycle," said Tony Asaro, analyst with the Enterprise
Strategy Group (ESG). According to Asaro, ESG Research surveyed 511
companies and found that 17% of these companies were already using
iSCSI and another 20% planned to in the next 24 months. "Of the
early adopters, 50% were already using iSCSI for Tier-1
mission-critical applications, and 37% of planned adopters intended
on using iSCSI for Tier-1 mission-critical applications. "
Web-based software and mobile information services company
AirClic U.S.A., based in Newtown, Pa., also has had no qualms about
storing Oracle data on iSCSI. AirClic told SearchStorage.com that
it had also tested the NetApp system Dow Chemical plans to use, but
found EqualLogic Inc.'s latest SAS-based array, the PS3800XV, a
better deal for both cost and manageability over both NetApp and
EMC.
When it began to explore networked storage again over the winter
of 2005 and 2006, AirClic set out to purchase an IP SAN from the
start because of the lower costs as compared to Fibre Channel and
the ability to use standard NICs and Cisco Systems Inc. networking
switches.
Five years ago, according to Andy Monroe, vice president of
technology at AirClic, the company had run a Compaq Fibre Channel
SAN, but a reorganization left that technology stagnating on the
floor. Currently, the company's services include processing data
from mobile phones, barcode scanners and sensors in a customer's
environment, which AirClic then runs through an Oracle database in
order to model workflows for the customer. So, for example, a
company employing security guards could receive reports from
AirClic on whether or not its employees, wearing devices that
trigger sensors in the environment, have made assigned rounds.
Monroe said he never had any qualms about putting the company's
production Oracle database on iSCSI storage. "There's a perception
that iSCSI isn't for a high performance database," he said. "But
for our purposes, throughput speed over Fibre Channel didn't make
as much of a difference as drive speed -- 1 Gbps, 2 Gbps or 4 Gbps
was not as relevant for us as drive speed for processing
information out of our database."
When considering a SAN this time around, the company went for
EMC's Clariion first, and also considered NetApp.
EqualLogic beats out EMC and NetApp
In testing, however, "we were able to get the same results in
our testing of the [EqualLogic] PS3800 against an EMC CX500i -- the
same total number of disks and speed of disk at 15,000 rpm, for a
lower cost," he said. In tests running small random I/Os using
Oracle's Orion Calibration tool, which is designed to simulate
Oracle workloads, Monroe said, "we were seeing about 4,000 IOPS on
the EMC unit and about 4,200 IOs per second (IOPS) on the
EqualLogic unit when using Iometer."
He added, "We were trying to isolate the performance of the
disks and also be sure there wasn't any real difference between
iSCSI and Fibre Channel with those types of workloads."
Along the line, AirClic also evaluated NetApp's FAS270 array.
According to Monroe, NetApp brought in one of its own engineers
with the 270 and spent five hours trying to get the test machine, a
Dell 2850 running Windows server 2003, set up. "They used several
service packs and couldn't get the logical unit numbers (LUN) to
present to the server," he said.
According to Monroe, even once it was up and running, the
graphical user interface (GUI) was not intuitive. "We couldn't
figure out how to create a volume, or perform iSCSI authentication
intuitively -- we found ourselves going through a lot of
documentation," he said. "The impression I got was that this unit
was really aimed at being used for Fibre Channel and had iSCSI
support just added on top of it."
After exhausting those options, Monroe was referred to
EqualLogic by a reseller, and quickly decided to purchase after
being sent a test PS100 array in January.
"We are not storage experts by any means," Monroe said. "But we
got that one up and running in 20 minutes."
Several months later, AirClic became a beta tester and then an
early adopter of EqualLogic's new SAS array, the PS3800XV -- in
all, the company's networked storage environment today comprises 6
TB, most of it on 15,000 rpm SAS drives on the newer array.
The SAS drives, Monroe said, helped assuage any worries about
another iSCSI problem -- reliability. EqualLogic's automatic load
balancing within its modular arrays and hot-swappable components
also helped, he said.
Moreover, analysts said that AirClic isn't necessarily in the
minority -- the traditional performance and reliability worries
about iSCSI, especially in small and midsized enterprises, are
becoming a thing of the past.
"I am seeing more smaller enterprises put IP SAN on their
roadmap for mission critical workloads. Over the next 24 months,
this will become a completely standard expectation from customers
-- the economics will be very compelling," said Brad O'Neill,
senior analyst with the Taneja Group.
Not perfect by any means
Though he's happy with its reliability, management and cost,
using the EqualLogic array hasn't been a totally ideal experience
with his Oracle database, Monroe said. He still prefers to use (and
manage) a separate tool for backup -- Oracle's Hot Backup and
Oracle's DataGuard for replication -- rather than the baked-in
snapshot and asynchronous replication capabilities offered with
EqualLogic's arrays.
Another issue is EqualLogic's support for Linux. "Oracle prefers
to run on Linux," Monroe said. "That's just the nature of the
application." But while EqualLogic offers what Monroe calls
"fantastic support" for Windows applications, including
multipathing for better traffic throughput and failover within the
array using Microsoft's software iSCSI initiator, on the Linux
side, a software initiator has to be combined with a costly
hardware host bus adapter (HBA) to get the same effect.
For now, Monroe said he simply mirrors his database server for
failover using an active-active cluster, "But a software initiator
that would support multipathing on the EqualLogic array would save
me that hardware cost," he said. "And if EqualLogic is trying to
get into the game to support all platforms, they could address this
gray area better."
"The issue that [Monroe] raised is valid…the difference between
Windows and Linux/Unix software initiators is not often discussed,"
said Dylan Locsin, public relations manager for EqualLogic, in an
email to SearchStorage."MPIO [multipath I/O] from Windows is a
great thing, and we'd love to see Linux operating systems have a
similar feature. Software initiators are best developed by the
operating systems suppliers, so building a better initiator is not
really an issue EqualLogic alone would solve."
According to Locsin, EqualLogic typically recommends that users
look into lower cost HBAs, such as those offered by Silverback
Systems Inc.. "These may be half the cost of previous products,
perhaps as low as $200 per port," Locsin said. "There are still
other reasons customers may want to have HBAs, as they still
provide boot-from-SAN capabilities."
Another option EqualLogic recommends users consider is NIC
teaming, a process of grouping together several physical NICs into
one through scripting. "Ultimately, this isn't as good as MPIO, but
in many environments it meets deployment needs," Locsin said.