What is important is that if the HAK is available for your Operating System, we need you to always install it on every host that attaches to IBM XIV. We ask this for the following reasons:
- By having the XIV HAK installed, your hosts are much easier for IBM to support. This is because installing the HAK ensures that your multipathing is setup correctly. When you installing the HAK and then run the xiv_attach command, the HAK will adjust system parameters to optimal values. For example on Windows hosts it ensures that the required MPIO Service is running and that the recommended hot fixes are installed. For Linux hosts it ensures that the multipath.conf file is correct. Every time you map a new volume from your IBM XIV, use should run xiv_attach to ensure you continue to have the correct settings.
- If you have an issue that requires IBM support, the HAK supplies a command known as xiv_diag. This command creates a zipped host log file that will contain useful and relevant information for IBM to analyze.
- The HAK supplies a very valuable command known as xiv_devlist which lets you list all attached volumes and match the host ID to the XIV volume name. If your host is attached to multiple XIVs, you can also map each volume back to it's relevant XIV. Its a command I cannot live without... I love it!
Here is an example of what xiv_devlist will tell you. In this example I have run it on a Windows 2008 machine, but the output is basically the same regardless of host operating system. You can see the operating system identifier (the Device as reported by the operating system, in my example PHYSICALDRIVE0), the name of the volume (as seen on the XIV, in my example W2K8X64-H02_BOOT - Exchange) and the serial number of the XIV providing the volume (in my example 6000081)
The operating system device identifier lets you map an XIV volume from XIV to host. So in this example, I know that the Windows (C drive, which is Windows Disk 0, maps to a volume on the XIV known as W2K8X64-H02_BOOT - Exchange.
And to finish, there are several other commands that are very helpful. For instance thexiv_fc_admin -P command will tell you your WWPNs.
C:\Windows\system32> xiv_fc_admin -P 21:00:00:0d:60:13:b0:8c: [QLogic IBM FCEC Fibre Channel Adapter]: IBM FCEC 21:00:00:0d:60:13:b0:8d: [QLogic IBM FCEC Fibre Channel Adapter]: IBM FCEC
Another useful command is xiv_fc_admin -R because it rescans your bus. In some operating systems it is not obvious how to do this (other than reboot of course).
The nice thing is that regardless of your host operating system, the commands are the same. This is possible because they use the Python programming language. You may notice Python being installed as xpyv when you install the HAK (it is so named to ensure it doesn't interfere with any other Python installs you have).
So please install the HAK on every host that attaches to XIV. You will be making everyones life a lot easier (especially your own).
Oh and by the way, you can confirm whether your Host Operating System can be attached to the XIV by consulting the IBM System Storage Interoperation Center (or SSIC). If the HAK is not available for your Operating System, the SSIC will list other Vendor approved multipathing solutions (such as Veritas DMP).