Troubleshooting CRC Errors On Fibre-channel Fabrics There is no "Easy Button" for troubleshooting CRC errors. It is an iterative process. You make a change, you monitor your fabric, and if necessary you make more changes until the issues are resolved. I frequently have customers who want it to be a one step process. It can be, but usually takes multiple steps. Having said that, before we can fix them, we need to know what CRC errors are and why they occur. What Are CRC Errors? When Do they Occur? The simple answer is that CRC errors are damaged frames. The more complicated answer is that before a fibre-channel frame is sent, some math is done. The answer is added to the frame footer. When the receiver gets the frame, the receiver repeats the math. If the receiver gets a different answer then what's recorded in the frame, then the frame was changed in flight. This is a CRC error. The only time these happen is if the physical plant - cabling, SFPs is somehow
Showing posts from April, 2019
- Other Apps
IBM released a new Alert Policies feature for IBM Storage Insights Pro the first week of March 2019. John Langlois does an excellent job introducing the new feature here: There are a few more advanced aspects of alert policies that John did not cover. First, you can add and remove managed storage from Alert Policies from the Alerts Definitions of the storage system that you want to modify. The following video shows how to do this. Second, you must remember that if you add storage that has never been in an Alert Policy to an Alert Policy, any existing alerts defined on that storage are lost and cannot be retrieved. The following video shows an example managing of this and shows a workaround to preserve those alerts if you want to re-apply them at some point in the future.