AIX Host Settings

DataCore Support for AIX MPIO Software

Download and install the DataCore Support for AIX MPIO software package on the AIX Host. Installation and configuration instructions can be found from the following link: https://datacore.custhelp.com/app/answers/detail/a_id/1419

Disk Timeouts

rw_timeout and hcheck_interval settings

Set the ‘rw_timeout’ to 60 seconds and the ‘hcheck_interval’ to something equal to or higher than the ‘rw_timeout’ setting - as per IBM’s own recommendations.

Use the following command to change both the ‘hcheck_interval’ and ‘rw_timeout’ values at the same time:

chdev -l hdiskX -a hcheck_interval=90 –a rw_timeout=60 -P [1]

A reboot of the Host is required to make these settings permanent.

Enable Fast I/O Failure

Use the following command to enable Fast I/O Failure for all Fibre Channel (FC) devices:

chdev -l fscsiX -a dyntrk=yes -a fc_err_recov=fast_fail -P [2]

Device Queue Depth

Set the Device Queue Depth for all served DataCore virtual disks (vDisks).

  1. Identify the DataCore vDisk.

The following example shows 'hdisk2' as the DataCore vDisk.

# lsdev -Cc disk
hdisk0 Available 10-80-00-4,0 16 Bit SCSI Disk Drive
hdisk1 Available 10-80-00-5,0 16 Bit SCSI Disk Drive
hdisk2 Available 10-90-01 Other FC SCSI Disk Drive
  1. Get the disk device's attributes.
# lsattr -El hdisk2
…
queue_depth 1 Queue DEPTH True
...

In the example above, the queue depth value is 1.

  1. Set the value to 16.
# chdev –l hdisk2 –a queue_depth=16
  1. Verify the change.
# lsattr -El hdisk2
…
queue_depth 16 Queue DEPTH True
...

16 is the value that DataCore use when qualifying AIX. Larger values are possible up to and including 32. Larger values are not supported. Smaller values are also possible but may reduce Host performance for DataCore vDisks.

Also See

Path Health Check Settings

Fast I/O Failure for Fibre Channel devices