CISCO-FC-SDV-MIB

This MIB instrumentation is for managing Fibre Channel (FC) SAN Device Virtualization (SDV) solution on Cisco Fibre Channel devices. Glossary of the terms used in this MIB: --------------------------------------- Config Commit - User initiated action that triggers commiting of configuration to local device/fabric. Eg. CFS based config 'commit' as described in CISCO-CFS-MIB. Domain - The highest or most significant hierarchical level in the three-level FC addressing hierarchy. Device Aias - is a string which can be used to alias a World Wide Name (WWN). FCID - Fibre Channel Address ID. A 24 bit Fabric unique address identifier. FCNS - Fibre Channel Name Server. Initiator - The system component that originates an I/O command over an I/O bus or network. NWWN - WWN associated with FC node. PWWN - WWN associated with FC port. Real Device - A hardware entity which includes Link Control facility. It is directly connected to a FC fabric and acts as originator/responder or both. RSCN - Registered State Change Notification. RSCN Notifications are sent to Nx_ports and other switches to notify that an event has occurred. SW_RSCN - Switch Registered State Change Notification. SW_RSCN Notifications are sent to neighbouring switches in a fabric to notify that an event has occurred. SCSI - Acronym for Small Computer System Interface. Target - The system component that receives a SCSI I/O command command. Virtual Device - The virtual initiator/target having its (VD) own device identity and proxies a Real Device (Initiator/Target) in a FC fabric. VT - Virtual Target. VI - Virtual Initiator. Virtual Domain - A logical Domain partition in a FC fabric within which a Virtual Device exists. VSAN - Virtual Storage Area Network, similar to a VLAN. WWN - Wide Name (WWN) associated with a Fibre Channel (FC) entity. A 64 bit identifier, with a 60 bit value preceded with a four bit Network_Address_Authority_Identifier, used to identify physical entities in Fibre Channel. The primary motivation for SAN Device Virtualization is the High availability of storage disk arrays with no downtime. Redundancy is achieved by duplication of information and hardware to ensure secondary device can take over the function of a primary device when the latter fails. The initiators (servers) perform I/O to the primary target. The secondary target is kept in sync to have a mirrored copy of the primary target by a replication mechanism. In the event of a disruption to primary target, all I/O must be immediately re-routed to secondary target so that services running on initiators remain un-interrupted. The SDV solution resides on a Cisco FC Switching Device. The target failover is achieved by presenting a virtual proxy target to initiator with the SDV acting as a conduit for creating and deleting the proxy (virtual) target on demand. The Virtual Target or in general Virtual Device can virtualize (proxy) set of Real Devices with one Real Device actively mapped as the primary mapping and the rest as secondary mappings. WWN2,FCID2 _____ | | [Switch Fabric] /| RT1 | ''''''''''''''' / |_____| WWN1,FCID1 ' ' / [Primary Real ____ ' WWN4,FCID4 ' / Target Device] | | ' +~~~~~~~+__'_/ | I |->--->'->| VT |__'_ |____| ' +~~~~~~~+ ' \ [Real Host ' ' \{On Fail-Over} (Initiator)] ' ' \ WWN3,FCID3 ''''''''''''''' \ _____ [VT: Virtual Target] \| | | RT2 | |_____| [Secondary Real Target Device] -<< Fig 1 >>- In the above figure (Fig 1), 'Switch Fabric' presents the Virtual Target 'VT' as a proxy device for real targets 'RT1' and 'RT2'. The Host/Initiator 'I' can discover a virtual target VT and does not see real targets RT1 and RT2 as accessible targets. The Virtual Target VT is configured on the switch and maps to one real target as a primary mapping. The Initiator performs I/O with VT. When the primary target RT1 fails, the secondary real target RT2 can take over. For the Initiator, failover/migration is transparent and continues to perform I/O with VT. ___ ____ ____ | |-->--[I->VT]-----[ ]---->--[I->T]---| | | I | [ VT ] | RT | | | [ ] | | |___|--<--[I<-VT]-----[____]----<--[I<-T]---|____| [Initiator] [Virtualized [Real Target] Target] -<< Fig 2 >>- When the Initiator 'I' performs I/O with VT, the SDV enabled switch performs FCID address translation to route FC frames to the real target RT (refer Fig 2). The I->VT frames are translated as I->T. The T->I frames are translated as VT->I. The SDV manages VT so that other devices (in the same zone) perceive it as just another device in the fabric. The cFcSdvVirtDeviceTable is table of Virtual Devices. The cFcSdvVirtRealDevMapTable is a table of mapping elements. A Virtual Device is represented by a row in the cFcSdvVirtDeviceTable, and if its value of cFcSdvVdRealDevMapList has the value of zero, then the Virtual Device is not currently mapped to any Real Devices. Otherwise, the Virtual Device is mapped to the set of Real Devices with each Real Device identified by the instance indentifier value of cFcSdvVirtRealDevMapIndex.