This article can also be found in the Premium Editorial Download "Storage magazine: Backup overhaul: From a mainframe to an open-systems environment."
Download it now to read this article plus other related content.
Bumps in the road
With new technologies come the typical bumps in the road that can take hours, days or even weeks for users to diagnose and fix. For example, users of QLogic's QLA4050C iSCSI HBA may encounter an "error code 10" message when they try to load the HBA's driver. QLogic found that this error code stemmed from the inability of the BIOS on new server systems to read the BIOS of their iSCSI HBAs. To correct the problem, you must install a new driver available through QLogic's support Web site (after first opening a call with QLogic support).
For users looking to connect high-performance servers to an iSCSI SAN, diagnosing performance problems with iSCSI HBAs becomes a more complicated and time-consuming proposition. Two features that are critical to tuning performance in an iSCSI SAN are the iSCSI card's flow control and jumbo frame settings.
In iSCSI NICs and HBAs, the flow-control feature is typically turned on by default to improve performance and control the flow of data between the iSCSI HBA and an Ethernet switch. The purpose of flow control is to enable lower speed devices to communicate with higher speed ones, and to monitor the flow of traffic from the HBA to the Ethernet switch.
This was first published in April 2007