The Storage Array Type Plugin (SATP) is part of the vSphere storage multipathing stack, which helps handle storage array related events. vSphere contains a NetApp claim rule that utilizes the default VMW_ALUA_SATP plugin, which is specifically designed for use with Asymmetric Logical Unit Access (ALUA) capable storage arrays, when the storage controller is using ALUA configuration. This article describes the procedure to add a claim rule that enables the
reset_on_attempted_reserve option for NetApp devices using the ALUA SATP.
reset_on_attempted_reserve option is used to allow a LUN Reset to be sent to a storage array when an attempted
Reserve(6) command fails to get a response due to a fault condition, such as switch port down or storage controller failover events. The storage array will perform a logical unit reset upon receiving the LUN Reset request, clear all reservations, and report a Power On or Reset (POR) status. Having the
reset_on_attempted_reserve option helps the vSphere hosts to recover from a lost reservation attempt or a lost reservation response, which could result in I/O not making progress until the device is reset.
NetApp strongly recommends setting the
reset_on_attempted_reserve option on all VMware vSphere 4.x and 5.x hosts where VMFS dastores are used. This will minimize reservation related disruptions sometimes observed after a storage fabric or storage controller fault event. This recommendation is applicable to FC/FCoE 7-Mode SAN ALUA configurations and all FC/FCoE/iSCSI Cluster-Mode SAN configurations.