EMC clears the path for automated fail-over and load balance

In the corporate world, time is money, and in an era when business hours have been extended from nine-to-five to 24×7, any downtime is lost revenue. EMC Corp.’s PowerPath software attempts to address this issue by providing end-to-end automated path fail-over for networked storage environments.

PowerPath is designed to deliver this automated path failover from the server, through the network switch and to the storage system. The software also enables the server to continue processing I/O requests to an alternate fibre channel adapter in the event of path failure.

According to Mike Stivaletti, area SE manager for EMC Canada in Toronto, “PowerPath is a software product that allows us to load balance.”

Geoff Haydon, managing director and country manager of EMC Canada suggested that there are two challenges that the software addresses.

“Often performance demands overwhelm your connection or if you lose that channel or that connection, you can’t effectively access information on your storage device,” he said. “The software also addresses business continuance.”

It’s something that’s always been optimal, but not demanded or expected by companies until fairly recently.

“Going back a few years ago, if you had connections to a storage device and lost a path, your data became unavailable to you,” Stivaletti said. “Work would stop. With PowerPath, you take two paths and can present 10 devices to them. The devices are seen by both paths, so if you lose a path, the other path can still see all 10 devices with the failover capability. In a failure mode, if you lose one path you lose half of your devices. With PowerPath, if you have two paths running 50 per cent each and one goes down, the other path runs 100 per cent. That’s an extreme example, but that’s how it works.”

Haydon explained that although the importance of business continuance has been a hot topic for some time, interest has grown tremendously since the events of Sept. 11.

“Obviously there’s an interest in disaster recovery and business continuance, and the management of information is exceptionally topical,” he said. “Interest has intensified since Sept. 11.”

Bud Michels, CEO of CSP Corp. in College Park, Md., and a PowerPath customer, has found the automated path failover component to the software to be invaluable.

“We have about 40 servers, and about 34 of them are in our SAN. In one case one of them failed – it was the host bus adapter. We were notified at 3:30 in the morning by EMC’s customer service people telling us that there was a problem, but was the system down? No. We saved ourselves a lot of money by having PowerPath.”

Because, as Michels explained, CSP is an “EMC shop” as far as what they run, interoperability is not much of an issue, however, it is at the top of the list for many companies looking for storage software, according to Toronto-based IDC Canada analyst Alan Freedman.

“Right now interoperability is number one in customers’ minds,” Freedman said. “They shop around and see which vendors offer what meets their needs now and their future needs. They don’t necessarily want to pay for every feature and functionality out there, but what they need to integrate the product into their infrastructure.”

EMC has designed PowerPath with interoperability being a top priority.

“Interoperability is a key tenet for us,” Haydon said. “We want it to be an enabling, not an inhibiting technology.”

To date, the company has tested and qualified interoperability between its storage systems and nearly 400 server models, 40 operating systems, 81 storage software products, 145 network elements and 1,200 devices including HBAs, drivers, switches and tape subsystems. According to Haydon, the company has invested $1.5 billion on ensuring interoperability to its customers.

“It’s a function of the fact that we’ve been in the industry for a long time,” he said.

PowerPath supports Novell NetWare 5.0, 5.1 and Novell Cluster Services 1.1, Windows NT/2000, IBM AIX, Sun Solaris, HP-UX and Compaq Tru64.

Information about EMC’s PowerPath storage software can be found at http://www.emc.com.