Sadek, Abdel napisał(a): > Hello; > we need to understand how it works in order for our developers to make it work with our own multipath driver. Hello, scsi_reserve and fence_scsi do not work with multipath environments. scsi_reserve do registration and reservation at startup, and fence_scsi do unregister. Here is some information form conversation with Ryan O'Hara - person who wrote fence_scsi and scsi_reserve scripts. --cut--- There are a few reasons for this. First, it is possible the creating registrations/reservations at startup and unregistering at fence time could ping-pong the I/O paths. That is assuming that I/O down either path will automatically switch the active I/O path. So at best it would work with only active/active controllers. Second, discovering the I/O paths in a multipath environment does not work. All devices (I/O paths in this case) must be registered, so each node must create a registration for each device (I/O path) using its key. This also does not work. Finally, fencing is unreliable with scsi reservations in a multipath environment. For example, suppose an I/O path fails for one node. Assume that node is selected to fence another node. It will need to unregister the key for the faulty node for all I/O paths. If the node responsible for performing fencing does not have all I/O paths available, it will not be able to unregister the key for the faulty node. This is very problematic. These are a few reasons why you cannot use scsi reservations as a fence method in a multipath environment. ---cut--- For my opinion You have two choices: 1. Change multipath driver to work correctly with scsi fencing 2. Change firmware in You storage where there it only check of host ID. In this situation WWN of HBA isn't checked and You can connect all of You pathes. Please give me also information which multipath driver do You use. Hope this makes sense. Best Regards Maciej Bogucki -- Linux-cluster mailing list Linux-cluster@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/linux-cluster
