scsimgr SCSI Management and Diagnostics utility on HP-UX 11i v3 (March 2008)

scsimgr: LUN /dev/rdisk/disk100 disabled successfully
# ioscan -P health /dev/rdisk/disk100
Class I H/W Path health
===============================
disk 100 64000/0xfa00/0x15 disabled
Notes:
• When all lunpaths to a LUN are disabled, applications can no longer open the LUN, and
attempts to open the LUN will fail with the following error: ‘no such device or address’.
• The system performs critical resource analysis (CRA) when the user requests to disable a
lunpath or a LUN. If the lunpath or the LUN is critical for the operation of the system (for
instance root/boot device), the system notifies and fails the operation.
To enable a lunpath, which was previously disabled
# scsimgr enable -H 0/4/1/0/4/0.0x50001fe150006e69.0x400f000000000000
LUN path 0/4/1/0/4/0.0x50001fe150006e69.0x400f000000000000 enabled successfully
To enable a disk device, which was previously disabled
# scsimgr enable -D /dev/rdisk/disk100
scsimgr: LUN /dev/rdisk/disk100 enabled successfully
Enabling I/O transfer to a LUN after fixing an unrecoverable deferred
error
When the SCSI stack detects that a device has experienced an unrecoverable deferred error, or a
change of I/O block size, it disables the device for I/O transfer and logs a message to alert the
system administrator. For example if an unrecoverable error occurred on disk100, the SCSI stack will
log a message similar to the following:
An unrecoverable deferred error occurred on the device dev=0x0b000015, lba=0x0020f0.
The LUN has been disabled to minimize any further loss of data integrity.
The LUN may be enabled by running : scsimgr enable -D <raw_lun_dsf> after
the content of the LUN has been restored from the last known good copy.
After restoring the content of disk100, run the following command to re-enable I/O transfers:
# scsimgr enable -D /dev/rdisk/disk100
scsimgr: LUN /dev/rdisk/disk100 enabled successfully
Activating lunpaths in standby or active non-optimized states for devices
supporting asymmetric access
The following examples show how to determine if a device support asymmetric access and when it
may be necessary to run the ‘scsimgr activate’ command on such devices.
The ‘scsimgr activate’ command applies to devices supporting explicit asymmetric access. A
specific SCSI command can be sent to these devices to change the asymmetric access state. The
‘scsimgr activate’ command activates lunpaths of the device in ‘STANDBY’ or ‘ACTIVE/NON-
OPTIMIZED’ asymmetric state. On HP-UX 11i v3, the mass storage recognizes the following
categories of devices as supporting explicit asymmetric access:
• Devices implementing the T10 Asymmetric Logical Unit Access (ALUA) standard, and which
report support for explicit or both explicit and implicit asymmetric access.
40