Compellent Technologies has added setup automation and boot-volume
consolidation to the software package that comes with its
StorageCenter
storage area networks (SAN), which the company claims will make
provisioning boot disks on the SAN easier and cut costs for
everything from server purchases to failover via the
WAN.
The new Server Instant Replay feature keeps a golden copy of
each operating system (OS) and then uses snapshot pointers for each
physical server pointed to the SAN to keep track of things, like
registry or dll changes, in the case of Windows. Once the operating
system is loaded onto the Compellent SAN, a new wizard, now
included with the software, walks users through the process of
pointing their server to the correct operating system golden copy
boot volume.
Compellent claims that the majority of its 500-plus customers
use boot from SAN capabilities, which it has offered since the
first generation of its product. The company also estimates that
typically, boot-volume provisioning takes SAN administrators about
eight hours.
"If you multiply that by 25 servers, that time adds up quickly, as
does the storage space for all those boot volumes," said Bruce
Kornfeld, vice president of marketing for Compellent.
It's really more like three hours for a typical setup, according
to Steve Tilton, manager of networked systems for the Maine Public
Broadcasting Network. The network currently has 26 servers, about
half of them running Windows Server 2003 and the rest running
Netware, Windows NT 4 and Sun Solaris, which it already boots
through two Compellent SANs in Bangor and Lewiston, Maine.
Still, he said, "Not having to take the time every single time
you add a server to configure the Microsoft OS could conceivably
cut our setup time in half."
Another user, Nick Colakovic, director of IT for First
Industrial Realty Trust Inc., headquartered in Chicago, said the
consolidation of boot volumes will save him a total of 1 terabyte
(TB) of storage space over two locations when all is said and done.
The company has a 16 TB capacity on the company's main data center
SAN in Mount Prospect, Ill., and 11 TB at its corporate
headquarters in downtown Chicago. "Our standard allocation for a
boot volume is about 10 GB," he said. "If you multiply that times
55 servers, which is the number we have, it's not an
inconsequential savings for us."
First Industrial's headquarters is located right next to the
Sears Tower, and the company's IT infrastructure has been designed
with that building's potential for disaster in mind. The company's
headquarters is actually the secondary data center for this reason,
Colakovic said, and the two sites use Compellent's replication
features to synchronize data nightly for disaster recovery
purposes.
When it comes to the boot-from-SAN consolidation, Colakovic said
another big benefit for him will be the potential change in
recovery time rather than setup time. "Having to pull the entire
server image over the wire for every server and then add all the
changes for each boot volume could triple our recovery time in the
event of a failure," he said.
Storage/operating system partnerships?
"I'm very positive about boot from SAN, especially to improve
availability and recovery, and at the alternate site," said
Stephanie Balaouras, senior analyst with Forrester Research Inc.
"But I'm also aware of how complex it is -- it requires the proven
interoperability of a lot of components beyond the array -- and
partner and technology agreements and cooperation are
critical."
Compellent, however, would beg to differ. "The solution doesn't
require that we have agreements with server/OS vendors," argued
Compellent spokesman Rob Davis. "Part of Storage Center's code is
based on Java to allow us to talk to servers of any OS. Then we
take advantage of the server's native failover -- a part of the OS.
If a new OS were to come out, we would issue a patch to Storage
Center so that the SAN would automatically recognize those servers
as well."
But Balouras argued, "it will only be a meaningful announcement
if they come to market with partners who support the solution. I'd
want to see Microsoft and VMware at a minimum given the
proliferation of server virtualization."
Calakovic said the lack of formal support agreements between
Compellent and Microsoft doesn't bother him. "What does that
actually mean?" he asked. "It becomes a metaphysical issue -- the
only real issue would be I/O timeout on a boot volume, but if the
storage performs reasonably well, that's not a problem."
Still, Calakovic said, the lack of support from Red Hat Inc. for
boot from SAN for his Linux hosts has at times proved a hassle. "It
still works fine," he said. "There's just a lot of manual
refinements you have to do on Red Hat to set it up on a SAN because
of Red Hat's reticence to support boot from SAN, which I think is
childish."
Red Hat's opposition to boot from SAN is
publicly documented; the company will only
formally support boot from local disk.