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Surviving microcode upgrades

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Tier-1 upgrades more stable
The upgrade process is a little more seamless and stable with Tier-1 storage. For example, each CPU in EMC's Symmetrix DMX (there can be as many as 100) is upgraded one at a time. PowerPath/SE assists with the same failover in the Symmetrix as in the Clariion, except that new versions of the operating environment are loaded CPU by CPU within the timeout limits of the host OS in a matter of seconds.

Joe Meyer is the senior storage architect at Level 3 Communications Inc., a 350TB EMC shop in Broomfield, CO. Two years ago, he notes, the timeout issue wasn't handled quite as smoothly and the EMC Symmetrix 68 code "could be problematic." There were timeouts of 20 to 30 seconds, which were potential risks to his Oracle applications. To avoid the problem, Level 3 "cycled through the arrays, upgrading them one at a time offline," he says.

Since then, says Meyer, EMC has improved the process considerably. The current code is well within the timeout values for a major revision change. "Once a quarter, we patch the Symms and it goes without a hitch," he says. As a rule, Level 3 schedules EMC to perform upgrades in off-business hours. Meyer says his company doesn't implement every patch, preferring to wait for bundled revisions to limit the number of times he has to fiddle with the environment. "We patch only when we're experiencing a serious problem," he says. The latest version of the Symmetrix OS, called Engenuity

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and known internally as 71 code, has been available for more than a year, but Level 3 won't be installing it until the first quarter of this year. "The value of those new features didn't outweigh the potential risk of bugs in the new code," says Meyer.

3PAR supports non-disruptive code loads
Because of the nature of its operations, Factiva, a Dow Jones & Reuters Company, has little tolerance for downtime. As a result, its Hewlett-Packard (HP) Co. Enterprise Virtual Array (EVA) products had to be augmented with something that would support non-disruptive code loads.

Understanding upgrades: What to ask vendors
  • Can I perform a write while the upgrade is occurring?
  • Is it possible to establish a new session?
  • What services aren't available during an upgrade?
  • What happens to the performance of the system during an upgrade as processing power is used for the upgrade?
  • How many microcode upgrades have been issued this year for this model?
  • Which hardware components can be hot-swapped? What's the maximum downtime to expect with component replacement?
  • What guarantees against downtime are offered for code or component upgrades?

"Our business is a 24/7 global operation; there's always someone, somewhere, working," says Karin Borchert, chief operations officer at Factiva. The company turned to 3PAR Inc., Fremont, CA, purchasing three of the startup's InServ Storage Servers with high-availability features that include non-disruptive firmware upgrades. "We did move some of our critical data that required high availability from the EVA 5000s to the 3PAR," the company said in a written statement.

3PAR's InServ includes eight clustered controllers that communicate with each other in a mesh-like architecture. As with high-availability server clusters, a portion of the 3PAR cluster can be upgraded while the other portion carries the workload. In addition, the data is striped across several hundred drives and multiple CPUs can be working on a single volume. This differs from the EVA and other traditional arrays that lay out data in splotches that are heavily dependent on a particular portion of the array.

"Simply put, we have different storage requirements for different applications, and the HP EVA 5000s satisfies some, while 3PAR satisfies others," says Diane Thieke, Factiva's director of global public relations.

HP offers a high-end storage array touted to support non-disruptive code upgrades. Dubbed the XP12000, it's a re-badge of Hitachi Data Systems' (HDS) TagmaStore Universal Storage Platform. Jacob Roersma, storage administrator at Priority Health in Grand Rapids, MI, is an XP12000 user and confirms that upgrades are non-disruptive.

There's "a rigorous process to make sure we stay in support with HBA drivers, tape libraries, etc.," says Roersma. "They [HP] run our environment through a matrix and then recommend what revisions we should be on." Despite the smooth upgrades, Priority Health maintains a dual-attached architecture that fails over from one controller to the other when upgrading.

This was first published in March 2006

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