Los dispositivos simétricos proporcionan el failback automático a una ruta óptima posible. Si se produce un failover en la ruta inicial, la ruta en espera se convierte en la nueva ruta en línea. En general, la ruta en espera es una ruta poco óptima. Cuando se activa el failback automático, se vuelve a conectar la ruta inicial y se produce automáticamente el failover de la ruta inicial.
# mpathadm list mpath-support mpath-support: libmpscsi_vhci.so
# mpathadm modify mpath-support -a on libmpscsi_vhci.so
# mpathadm show mpath-support libmpscsi_vhci.so mpath-support: libmpscsi_vhci.so Vendor: Sun Microsystems Driver Name: scsi_vhci Default Load Balance: round-robin Supported Load Balance Types: round-robin logical-block Allows To Activate Target Port Group Access: yes Allows Path Override: no Supported Auto Failback Config: 1 Auto Failback: on Failback Polling Rate (current/max): 0/0 Supported Auto Probing Config: 0 Auto Probing: NA Probing Polling Rate (current/max): NA/NA Supported Devices: Vendor: SUN Product: T300 Revision: Supported Load Balance Types: round-robin Vendor: SUN Product: T4 Revision: Supported Load Balance Types: round-robin . . .
Esta operación sólo se aplica a dispositivos de las dos categorías siguientes:
Dispositivos asimétricos con un mecanismo de failover de propiedad exclusiva, reconocido y compatible con rutas múltiples
Dispositivos que cumplen con el estándar T10 de compatibilidad con grupos de puertos de destino libmpscsi_vhci.so y proporcionan acceso a LU asimétrico de modo explícito
# mpathadm list lu /dev/rdsk/c0t600144F08069703400004E828EE10004d0s2 Total Path Count: 8 Operational Path Count: 8 /dev/rdsk/c0t600144F08069703400004E8183DF0002d0s2 Total Path Count: 8 Operational Path Count: 8 /dev/rdsk/c0t600A0B800026D63A0000A4994E2342D4d0s2 Total Path Count: 4 Operational Path Count: 4 /dev/rdsk/c0t600A0B800029065C00007CF54E234013d0s2 Total Path Count: 4 Operational Path Count: 4 /dev/rdsk/c0t600A0B800026D63A0000A4984E234298d0s2 Total Path Count: 4 Operational Path Count: 4 . . .
# mpathadm show lu /dev/rdsk/c0t600A0B800026D63A0000A4984E234298d0s2 Logical Unit: /dev/rdsk/c0t600A0B800026D63A0000A4984E234298d0s2 mpath-support: libmpscsi_vhci.so Vendor: SUN Product: CSM200_R Revision: 0660 Name Type: unknown type Name: 600a0b800026d63a0000a4984e234298 Asymmetric: yes Current Load Balance: round-robin Logical Unit Group ID: NA Auto Failback: on Auto Probing: NA Paths: Initiator Port Name: 210000e08b841feb Target Port Name: 200800a0b826d63b Override Path: NA Path State: OK Disabled: no Initiator Port Name: 210000e08b841feb Target Port Name: 200900a0b826d63b Override Path: NA Path State: OK Disabled: no Initiator Port Name: 210000e08b841feb Target Port Name: 200800a0b826d63c Override Path: NA Path State: OK Disabled: no Initiator Port Name: 210000e08b841feb Target Port Name: 200900a0b826d63c Override Path: NA Path State: OK Disabled: no Target Port Groups: ID: 5 Explicit Failover: yes Access State: active Target Ports: Name: 200800a0b826d63b Relative ID: 0 Name: 200800a0b826d63c Relative ID: 0 ID: 15 Explicit Failover: yes Access State: standby Target Ports: Name: 200900a0b826d63b Relative ID: 0 Name: 200900a0b826d63c Relative ID: 0
# mpathadm failover lu /dev/rdsk/c0t600A0B800026D63A0000A4984E234298d0s2
Si esta operación se realiza correctamente, el estado de acceso de los grupos de puertos de destino del dispositivo cambiará como resultado del failover de la unidad lógica.
# mpathadm show lu /dev/rdsk/c0t600A0B800026D63A0000A4984E234298d0s2 Logical Unit: /dev/rdsk/c0t600A0B800026D63A0000A4984E234298d0s2 mpath-support: libmpscsi_vhci.so Vendor: SUN Product: CSM200_R Revision: 0660 Name Type: unknown type Name: 600a0b800026d63a0000a4984e234298 Asymmetric: yes Current Load Balance: round-robin Logical Unit Group ID: NA Auto Failback: on Auto Probing: NA Paths: Initiator Port Name: 210000e08b841feb Target Port Name: 200800a0b826d63b Override Path: NA Path State: OK Disabled: no Initiator Port Name: 210000e08b841feb Target Port Name: 200900a0b826d63b Override Path: NA Path State: OK Disabled: no Initiator Port Name: 210000e08b841feb Target Port Name: 200800a0b826d63c Override Path: NA Path State: OK Disabled: no Initiator Port Name: 210000e08b841feb Target Port Name: 200900a0b826d63c Override Path: NA Path State: OK Disabled: no Target Port Groups: ID: 5 Explicit Failover: yes Access State: standby Target Ports: Name: 200800a0b826d63b Relative ID: 0 Name: 200800a0b826d63c Relative ID: 0 ID: 15 Explicit Failover: yes Access State: active Target Ports: Name: 200900a0b826d63b Relative ID: 0 Name: 200900a0b826d63c Relative ID: 0
Si la ruta a una LU está desactivada, el comando enable vuelve a activar la ruta. Se debe especificar la ruta completa con el nombre del puerto de iniciador, el nombre del puerto de destino y la LU. Para verificar el cambio, ejecute el comando show para la unidad lógica.
# mpathadm list lu /dev/rdsk/c0t600144F08069703400004E828EE10004d0s2 Total Path Count: 8 Operational Path Count: 8 /dev/rdsk/c0t600144F08069703400004E8183DF0002d0s2 Total Path Count: 8 Operational Path Count: 8 /dev/rdsk/c0t600A0B800026D63A0000A4994E2342D4d0s2 Total Path Count: 4 Operational Path Count: 4 /dev/rdsk/c0t600A0B800029065C00007CF54E234013d0s2 Total Path Count: 4 Operational Path Count: 4 /dev/rdsk/c0t600A0B800026D63A0000A4984E234298d0s2 Total Path Count: 4 Operational Path Count: 4 /dev/rdsk/c0t600A0B800029065C00007CF44E233FCFd0s2 Total Path Count: 4 Operational Path Count: 4 . . .
# mpathadm show lu Logical Unit: /dev/rdsk/c0t600A0B800026D63A0000A4984E234298d0s2 mpath-support: libmpscsi_vhci.so Vendor: SUN Product: CSM200_R Revision: 0660 Name Type: unknown type Name: 600a0b800026d63a0000a4984e234298 Asymmetric: yes Current Load Balance: round-robin Logical Unit Group ID: NA Auto Failback: on Auto Probing: NA Paths: Initiator Port Name: 210000e08b841feb Target Port Name: 200800a0b826d63b Override Path: NA Path State: OK Disabled: no Initiator Port Name: 210000e08b841feb Target Port Name: 200900a0b826d63b Override Path: NA Path State: OK Disabled: no Initiator Port Name: 210000e08b841feb Target Port Name: 200800a0b826d63c Override Path: NA Path State: OK Disabled: no Initiator Port Name: 210000e08b841feb Target Port Name: 200900a0b826d63c Override Path: NA Path State: OK Disabled: no Target Port Groups: ID: 5 Explicit Failover: yes Access State: standby Target Ports: Name: 200800a0b826d63b Relative ID: 0 Name: 200800a0b826d63c Relative ID: 0 ID: 15 Explicit Failover: yes Access State: active Target Ports: Name: 200900a0b826d63b Relative ID: 0 Name: 200900a0b826d63c Relative ID: 0
# mpathadm enable path -i 210000e08b841feb -t 200900a0b826d63b \ -l /dev/rdsk/c0t600A0B800026D63A0000A4984E234298d0s2
Esta operación desactiva la ruta de LU, independientemente de su estado de funcionamiento.
# mpathadm list lu /dev/rdsk/c0t600144F08069703400004E828EE10004d0s2 Total Path Count: 8 Operational Path Count: 8 /dev/rdsk/c0t600144F08069703400004E8183DF0002d0s2 Total Path Count: 8 Operational Path Count: 8 /dev/rdsk/c0t600A0B800026D63A0000A4994E2342D4d0s2 Total Path Count: 4 Operational Path Count: 4 /dev/rdsk/c0t600A0B800029065C00007CF54E234013d0s2 Total Path Count: 4 Operational Path Count: 4 /dev/rdsk/c0t600A0B800026D63A0000A4984E234298d0s2 Total Path Count: 4 Operational Path Count: 4 /dev/rdsk/c0t600A0B800029065C00007CF44E233FCFd0s2 Total Path Count: 4 Operational Path Count: 4 . . .
# mpathadm show lu /dev/rdsk/c0t600A0B800029065C00007CF34E233F89d0s2 Logical Unit: /dev/rdsk/c0t600A0B800029065C00007CF34E233F89d0s2 mpath-support: libmpscsi_vhci.so Vendor: SUN Product: CSM200_R Revision: 0660 Name Type: unknown type Name: 600a0b800029065c00007cf34e233f89 Asymmetric: yes Current Load Balance: round-robin Logical Unit Group ID: NA Auto Failback: on Auto Probing: NA Paths: Initiator Port Name: 210000e08b841feb Target Port Name: 200800a0b826d63b Override Path: NA Path State: OK Disabled: no Initiator Port Name: 210000e08b841feb Target Port Name: 200900a0b826d63b Override Path: NA Path State: OK Disabled: no Initiator Port Name: 210000e08b841feb Target Port Name: 200800a0b826d63c Override Path: NA Path State: OK Disabled: no Initiator Port Name: 210000e08b841feb Target Port Name: 200900a0b826d63c Override Path: NA Path State: OK Disabled: no Target Port Groups: ID: 8 Explicit Failover: yes Access State: standby Target Ports: Name: 200800a0b826d63b Relative ID: 0 Name: 200800a0b826d63c Relative ID: 0 ID: 18 Explicit Failover: yes Access State: active Target Ports: Name: 200900a0b826d63b Relative ID: 0 Name: 200900a0b826d63c Relative ID: 0
# mpathadm disable path -i 210000e08b841feb -t 200900a0b826d63b \ -l /dev/rdsk/c0t600A0B800029065C00007CF34E233F89d0s2