This article can also be found in the Premium Editorial Download "Storage magazine: Low-cost storage pieces fall into place."
Download it now to read this article plus other related content.
|Two ways to manage performance|
The agent problem
It's ironic, but performance-tuning software can create its own set of performance problems. As performance agents scamper from component to component, they clog the storage environment.
For this reason, Peter Galvin, CTO, Corporate Technologies says his company stopped selling and supporting such a product. When deployed, this product's agent consumed 10% of the server's CPU and generated additional network traffic.
Chris Gahagan, EMC's senior VP of infrastructure software, says that administrators should expect agents to consume no more than 1% to 2% of CPU and memory overhead. Any more than that, and the agent becomes obnoxious. He believes that to keep performance management agents at that level, they should only focus on gathering and monitoring high-level data. They should only consume more resources when they start to spot a problem thereby requiring more options to be turned on. However, once the problem is identified and solved, the agent should automatically throttle back to its default configuration.
Another problem is simply getting the agents on the servers, configuring them and maintaining them once they are there. Installing and configuring agents on 10 or 20 servers running Windows is one level of difficulty. Doing the same thing on a couple hundred servers with different operating systems and databases creates a whole new level of complexity. The good news is that there's progress to report on this front. EMC's Gahagan believes software agents should be self- propagating and distribute themselves to the servers running them. EMC is currently building an agent architecture that uses a distribution server to propagate agents to the servers it supports.
AppIQ hopes to minimize or avoid the whole agent issue by programming their central server to open a connection to either Microsoft's Windows Management Instrumentation (WMI) interface or the various Unix vendors' versions of it. Sun Solaris has had this functionality since Solaris 7, while IBM is currently preparing a version of it for their releases of Linux and AIX. Buyer beware: Many of these products are still in early stages of release.
Best bets for now
An administrator pondering what approaches to take for their performance-management needs should probably use a combination of point solutions in heterogeneous environments or tools from storage array vendors in homogeneous storage networks. Too many of today's tools designed for heterogeneous environments are either still in their infancy, are dying on the vine such as BMC's Storage Patrol, or only work in qualified heterogeneous environments where it works with a limited number of storage arrays and operating systems such as CreekPath Management Suite.
Of the point solutions that only get information from one operating system, database, switch or storage array, your time would be better spent tuning these applications, understanding them and getting them synced up in your environment than looking to any third-party tool. Performance management software will continue to be more of an exercise in brute force than an art form for the foreseeable future. Emerging standards, questions about functionality, tight budgets and the fact that measuring SAN performance is not a priority in most environments until something goes wrong will contribute to an overall procrastination in deploying this technology.
This was first published in October 2003