Whether or not 2007 becomes known as the
"
Year of iSCSI," more and more users are
making the transition between legacy
Fibre Channel (FC) systems and
iSCSI for production data. Two users, who recently made the
switch, said they've found performance and reliability on iSCSI
storage area networks (SANs) suitable for their purposes. But
management and configuration issues have, at times, led to bumps in
the road.
Last year the U.S. Army Corps of Engineers branch in Huntington,
W. Va., replaced a six-year-old Hewlett-Packard Co. (HP)/Compaq
HSG80 Fibre Channel array with an iSCSI SAN from LeftHand Networks
Inc. The Army Corps of Engineers had never been happy with the
complexities of managing a Fibre Channel SAN, but as IT specialist
Mark Kash said, "You make an investment, you don't just throw it
away. This is taxpayer money, and we had to suffer until we got
some kind of ROI out of it."
But dealing with the Fibre Channel SAN soon became so miserable
that Kash said his staff began provisioning new servers with direct
attached disk (DAS) whenever possible, rather than wrestling with
networked storage. The Amry Corps of Engineers tried DataCore
Software Corp.'s SANSymphony virtualization product to simplify
things, but the additional layer of software only added to the
confusion. After those experiences, Kash and his team chose
LeftHand for its ease of use.
Kash said the SAN's ease of use began with configuration and
didn't end there. "The speed is sufficient, I don't have to log in
via an obscure console, and any number of people in our department
can hook up an Ethernet cable very easily," Kash said. "With Fibre
Channel, there's one guy who knows how to do it."
However, there was one instance where the SAN may have been too
easy to use. One of the nonstorage administrators in the shop
accessed the SAN when trying to help users with a troubleshooting
problem, thinking the users were running up against volume size
limits.
"They were able to change the size of our volumes, not
understanding that what the users were really running up against
were quotas we'd set on purpose," Kash said. "That's one
disadvantage to ease of use -- people get in there thinking they're
trying to help and get a little too brave." Kash said he's since
strengthened the password.
Another of LeftHand's claims is that its SAN runs on
industry-standard server hardware, rather than requiring the
management of complex disk arrays. But Kash said there has been one
drawback to that feature -- LeftHand partners with server vendors
for underlying hardware. The Army Corps of Engineers' LeftHand
clusters started out running on MPC Corp.'s DataFrame 440 server.
But as of the release of SAN/iQ 7.0 this year, that particular
model from MPC wouldn't support the upgrade, according to Kash.
"LeftHand was really good about helping us get it replaced and
eating a big part of the cost," Kash said, but the hardware had to
be completely swapped out.
The Gem Group: Price right, MPIO a little trickier
Like the Army Corps of Engineers, promotional products
wholesaler The Gem Group had struggled along with an aging Fibre
Channel SAN, this time a Magnitude Classic from Xiotech Corp.
Initially, the IT folks at the wholesaler were uncomfortable with
iSCSI's reliability and whether or not it was "ready for prime
time," according to technology manager Brian Smith.
But Fibre Channel expertise was in short supply at Gem Group. "I
was the only one in our group that ran that portion of our
network," Smith said. "It was more difficult to manage, and there
are training issues and costs associated with all of that." When he
investigated newer products on the market, including SANs from
Compellent Technologies, EqualLogic Corp., LeftHand, Network
Appliance Inc. (NetApp), EMC Corp. and Pillar Data Systems Inc.,
Smith became convinced that iSCSI SANs were indeed ready for prime
time.
Smith liked the fact that Compellent and EqualLogic bundled in
features such as replication, rather than selling them as separate
licenses. "Xiotech and EMC were going to charge us somewhere in the
range of $50,000 to $75,000 more for the total package than it was
going to cost for Compellent or EqualLogic because we wanted
replication," he said.
After that, Smith still wasn't done pushing the vendors on
price. "Probably the biggest sticking point during our final
evaluation was the ability to extend the service for three years,"
he said. "EqualLogic gave us terms, but they weren't as
attractive." Smith declined to give specifics on the pricing of the
different service options.
The Gem Group went with a Compellent Storage Center SAN. Smith
finds the SAN's range of reporting capabilities make it easy to
use, and, he notes, "I haven't even looked into everything I can
use yet." However, Gem Group was still concerned about maintaining
the reliability of the system and decided to put in a multipath I/O
(MPIO) infrastructure connecting servers to the SAN via a QLogic
iSCSI host bus adapter (HBA) and Ethernet switch.
"Getting multipathing right took a little while," Smith said.
"You can't just plug everything in and then test it. We had to get
a procedure in place for setting up each element in the correct
order." Compellent's test and development lab had to get involved,
and it took several weeks to accomplish, but it did eventually
work.
Now that it's working, Gem Group "has the formula," and Smith
said he's happy with the support he received from Compellent during
the whole process. "They stuck with me," he said. "They wanted to
see it happen too."