Friday, August 15, 2008

Configuring MPIO for the virtual AIX client

Virtual SCSI Server Adapter and Virtual Target Device.
The mkvdev command will error out if the same name for both is used.

$ mkvdev -vdev hdiskpower0 -vadapter vhost0 -dev hdiskpower0
Method error (/usr/lib/methods/define -g -d):
0514-013 Logical name is required.

The reserve attribute is named differently for an EMC device than the attribute
for ESS or FasTt storage device. It is “reserve_lock”.

Run the following command as padmin for checking the value of the attribute.
$ lsdev -dev hdiskpower# -attr reserve_lock

Run the following command as padmin for changing the value of the attribute.
$ chdev -dev hdiskpower# -attr reserve_lock=no

•Commands to change the Fibre Channel Adapter attributes And also change the following attributes of the fscsi#, fc_err_recov to “fast_fail” and dyntrk to “yes”

$ chdev -dev fscsi# -attr fc_err_recov=fast_fail dyntrk=yes –perm

The reason for changing the fc_err_recov to “fast_fail” is that if the Fibre
Channel adapter driver detects a link event such as a lost link between a storage
device and a switch, then any new I/O or future retries of the failed I/Os will be
failed immediately by the adapter until the adapter driver detects that the device
has rejoined the fabric. The default setting for this attribute is 'delayed_fail’.
Setting the dyntrk attribute to “yes” makes AIX tolerate cabling changes in the

The VIOS needs to be rebooted for fscsi# attributes to take effect.

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