HP StorageWorks 2000fc HP StorageWorks MSA2000 Family MPIO DSM installation gu - Page 23

pgr Used for diagnostic and troubleshooting purposes only, the pgr (Persistent Group Reservations) command enables you to determine whether the DSM is currently using SCSI-2 Reserve and Release commands or SCSI-3 Persistent commands. It also enables you to specify which commands the DSM is to use. Typically, SCSI Reserve and Release commands are used in clustered environments where it is necessary to limit access to a target device to only one host at a time. Persistent Reservation refers to a set of SCSI-3 commands that replace the original Reserve and Release commands with a more sophisticated mechanism that provides better support for SAN and multipath configurations. The pgr command shows whether the DSM is currently using SCSI-3 Persistent commands and the PGR key. If the pgr command is enabled, the DSM uses SCSI3 Persistent commands. If the command is disabled, the DSM uses SCSI-2 Reserve and Release commands to reserve and release volumes on behalf of clustering software. The key is used to identify the host. dsmcli> pgr Persistent Reservation: Enable Key: T-W2K3-H The pgr command also enables you to specify which commands the DSM is to use. The change is not active until the system is rebooted. pgr [ enable | disable ] where: ■ enable specifies that the DSM use SCSI-3 Persistent commands ■ disable specifies that the DSM use SCSI-2 Reserve and Release commands pgr list The pgr list command displays the current persistent reservation status for all disk drives as seen by the current host. This information is used by service technicians when troubleshooting a problem. Installing the MPIO DSM 23