How to Disconnect a SCSI Controller

Disconnecting a SCSI device must be done with caution, particularly when dealing with controllers for disks containing critical file systems such as root /, usr, var, and the swap partition. The dynamic reconfiguration software cannot detect all cases where a system hang may result. Use this command with caution.

SCSI controller c1 provides an example of disconnecting a SCSI device.

1. Become superuser.

2. Verify the device is connected before disconnecting it.

   # cfgadm -al Ap_Id Receptacle Occupant Condition c0 connected configured unknown c0::dsk/c0t0d0 connected configured unknown c0::rmt/0 connected configured unknown c1 connected configured unknown c1::dsk/c1t10d0 connected configured unknown c1::dsk/c1t4d0 connected configured unknown

3. Disconnect a SCSI controller.

   # cfgadm -c disconnect c1 WARNING: Disconnecting critical partitions may cause system hang. Continue (yes/no)? y

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   Caution -

   This command suspends all I/O activity on the SCSI bus until the cfgadm -c connect command is used. The cfgadm command does some basic checking to prevent critical partitions from being disconnected, but it cannot detect all cases. Inappropriate use of this command may result in a system hang and could require a system reboot.

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4. Verify the SCSI bus is disconnected.

   # cfgadm -al Ap_Id Receptacle Occupant Condition c0 connected configured unknown c0::dsk/c0t0d0 connected configured unknown c0::rmt/0 connected configured unknown c1 disconnected configured unknown c1::dsk/c1t10d0 disconnected configured unknown c1::dsk/c1t4d0 disconnected configured unknown

   The controller and all the devices attached to it are disconnected from the system.