Compaq SAN good, not perfect
Fibre Channel scheme is impressive, but
storage management needs polish
By Henry Baltazar, PC Week Labs, PC Week
February 7, 2000
Compaq Computer Corp.'s Fibre Channel SAN is proof
that a well-tailored solution can be worth far more than
the sum of its parts. It also shows that storage area
network vendors are going after market share with more
than raw throughput numbers.
In PC Week Labs' tests, the Compaq SAN offered
impressive hardware redundancy and the ability to
support an environment with heterogeneous operating
systems — two criteria that have long been neglected by
SAN vendors, including Dell Computer Corp. and
Hewlett-Packard Co.
The key value-adds for the Compaq SAN solution, which
started shipping late last year, are the management
utilities that are bundled with the product and the
extensive interoperability testing that is done long before
a SAN is shipped to a production site.
Although impressive, the Compaq SAN is not perfect. In
tests, its storage management utilities were adequate,
but they were not as intuitive as the tools shipping with
HP's SANs (which the company gained when it acquired
Transoft Networks Inc.).
In addition, Compaq must expand its Secure Path
software to support operating systems besides Windows
NT so that everyone gets the same level of fault
tolerance.
From a hardware standpoint, none of the components in
Compaq's SAN solution are technically impressive. For
example, the core of our SAN was three Brocade
Communications Systems Inc. Silkworm Fibre Channel
switches, which IT managers can purchase from a
number of vendors.
Hardware redundancy
Per our specifications, the Compaq SAN emphasized
hardware redundancy to eliminate all single points of
failure. On each server host system and on each external
Fibre Channel storage enclosure, we configured dual
Fibre Channel HBAs (host bus adapters). Each controller
was wired to a different switch to give our servers and
storage units two distinct paths to the SAN.
In each storage unit, we also configured redundant RAID
controllers, with data changes mirrored to the caches of
both controllers.
Redundancy is extremely important because a single
failure kills not only one server, but also the entire
network. That said, redundancy can easily double or
triple the price of a SAN, which reinforces our
recommendation to wait before diving in.
At the core of the SAN, we had switches wired into a
mesh topology to ensure that there would be no
downtime in the event of a port or switch failure.
The key to successful failover and failback of our
Compaq SAN was Compaq's Secure Path management
package. In tests, we were impressed that Secure Path
was able to automatically detect data path failures that
we created (at the HBA, switch and fiber-optic cable
levels), and it successfully rerouted data transactions to
other pathways in a couple of seconds. The applications
we were running (including NetBackup) didn't fail
because of the lag.
The Compaq test SAN was designed to support two
Compaq ProLiant Windows NT servers and a Compaq
Alpha Server running the Tru64 operating system. The
SAN and the NetBackup software performed flawlessly in
this environment. We easily created backup jobs on
either server platform, and Compaq's SAN management
software let us control which servers had access to
specific data volumes.
In comparison, SAN management tools from Dell had
support for only NT servers.
Technical Analyst Henry Baltazar can be reached at
henry_baltazar@zd.com.
Executive Summary: Compaq Fibre Channel SAN
Compaq's Fibre Channel SAN
offering raises the bar for SAN
technology by beefing up
hardware redundancy and
supporting heterogeneous
networks. However, early
companywide adoption could cause trouble down the
road.
Short-term Business Impact: Get ready to shell out
the bucks because acquisition, implementation and
training will be extremely costly. At this stage, IT
managers should be launching isolated projects to
familiarize themselves with the technology and to gain
specific benefits, such as LAN-free backups.
Long-term Business Impact: Compaq's SAN will
eventually allow IT managers to not only simplify storage
management but also cut costs by sharing expensive
tape libraries and storage arrays between servers. As
standards compliance improves, SAN hardware will
become commodity items and will decrease in price,
which will allow IT managers to grow SANs less
expensively.
Fault tolerance; heterogeneous environment support.
Management tools and Secure Path work only on
NT.
Compaq Computer Corp.
Houston, TX
(800) 345-1518
Scoring Methodology
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