Using XIV with Symantec Dynamic Multi-Pathing

I got a question about Veritas DMP and XIV, so I thought I would write a quick post with some details on the subject.

A fundamental requirement for a host attached to a fibre channel SAN, is the use of multi-pathing software.  One alternative to achieve this (that IBM support for most operating systems attaching to XIV) is Symantec Dynamic Multi Pathing (DMP).   A nice way to find out whether this is the case for your particular operating system is to head to the SSIC, choose Enterprise Disk →  XIV Storage System → Your product version and then Export the Selected Product Version to get a spreadsheet of every supported environment.  Now under the multi-path heading of each page you will see what choices are supported.

Two key benefits of purchasing Veritas DMP  are that:

  • It works with heterogeneous storage and server platforms (so you could have EMC and IBM attached to the same server at the same time).
  • You can centrally manage all storage paths from one central management GUI.

Then the question becomes,  if I choose to go down the DMP route, do we still need the XIV Host Attachment Kit (HAK)?

The answer is a definite yes!

Veritas DMP and Solaris

If you’re using DMP with Solaris, when you run XIV HAK wizard, it will scan for existing dynamic multi-pathing solutions.  Valid  solutions for the Solaris operating system are Solaris Multiplexed I/O (MPxIO) or Veritas Dynamic-Multipathing (VxDMP). If VxDMP is already installed and configured on the host, it is preferred over MPxIO.

Veritas DMP and Windows

For a Windows host the important point is that Veritas Storage Foundation Dynamic Multipathing (DMP) does not rely on the native multipath I/O (MPIO) capabilities of the Windows Server operating system. Instead, it provides its own custom multipath I/O solution. Because these two solutions cannot co‐exist on the same host, perform the following procedure if you intend to use the Veritas solution:

  1. Install the Veritas Storage Foundation package (if it is not already installed).
  2. Restart the host.
  3. Install the IBM XIV Host Attachment Kit (or run the portable version).
  4. The HAK will perform whatever system changes it detects are necessary while still allowing DMP to perform the multipathing.  This may require a reboot (to install Windows hot fixes).

If the version of the Veritas Storage Foundation that you are using does not support the IBM XIV Storage System, install the Device Driver Installation Package 1 (DDI‐1) for Veritas Storage Foundation 5.1.  This update supports the IBM XIV Storage System.

As I said, the HAK will ensure that the required hot fixes are present.  These hot fixes are fairly important.  To understand what tasks the HAK will want to perform WITHOUT performing them, use the portable HAK and run:

xiv_fc_admin -i

This will tell you what tasks will be undertaken when you run the command without the -i parameter.  I detailed this behaviour here.

One benefit of the HAK is the wonderful xiv_devlist command.   Even if you are using DMP, the xiv_devlist command will still work, although you may need to specify veritas as per this example:

xiv_devlist -m veritas

Need more documentation?

This is all documented in the XIV Host Attachment Users Guide which you can find here
.

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About Anthony Vandewerdt

I am an IT Professional who lives and works in Melbourne Australia. This blog is totally my own work. It does not represent the views of any corporation. Constructive and useful comments are very very welcome.
This entry was posted in IBM Storage, IBM XIV and tagged , , , , , , , , . Bookmark the permalink.

9 Responses to Using XIV with Symantec Dynamic Multi-Pathing

  1. Nick says:

    Thanks Anthony. I’d also like to share from personal experience that it is fairly important to make sure that VSF is updated with the latest patches, and service packs if possible. For the latest software updates these are the two links to check

    for Patches
    https://sort.symantec.com/patch/matrix

    for DDI
    http://www.symantec.com/business/support/index?page=content&id=TECH155178

    Last I checked, the latest for Windows Server 2003/2008 is VSF 5.1 SP2 with CP8 and the latest DDI installed. The recommend method is to install the VSF Software, Cumulative Patch, and finally the DDI, then proceeding with the XIV HAK install. This is a time consuming process if your software outdated, as it requires multiple reboots in between.

    For those who can upgrade to VSF 6.0 which is available for Server 2008 X64 only. Lots of overall improvements with this version. There is also a DDI for this version.

    -Nick

  2. Javier Fernández González says:

    Anthony, I’m replaying from Spain. I really enjoy your blog and look forward new entries.

    Just now we’re migrating from a bunch of DS4700’s to a pair of MetroMirrored V7000. I have a question for you. The multipath drivers are both based in Windows MPIO. Can we have both drivers installed simultaneously in a Windows machine? This definitely would do our migration job easier…

    Best regards and great job!

    • Mixing MPIO drivers can be risky depending on versions. Some hosts our there are still using RDAC while some have moved to the LSIDSM. My experience with mixing SDDDSM with either of those is that it works fine, but don’t take that as a general rule. In principle the best thing to do is request your local IBM Pre-sales tech support to create a thing called a SCORE request to confirm your planned mix is supported.
      Hope this helps.

      • Javier Fernández González says:

        Thanks, Anthony, Of course it helps.
        All our Windows machines are using MPIO (LSIDSM) with STORport drivers. So we think we’ll mixing SDDDSM with these drivers, at least during the migration project.
        Again, thanks a lot!

  3. Oren H says:

    Thanks for this post.
    I have a relatively off-topic question, which bothered me recently:

    Why would a host admin prefer VxDMP over the *modern* OS’ native multipathing? Does it provide any advantage?

    Or is it being used simply because it’s bundled with Veritas Storage Foundation & HA, and is simply forced on Veritas users?

    • Solaris and HPUX clients historically used Veritas because it really was the best choice.
      Windows 2000 and 2003 customers often bought Veritas (especially in clusters) because it gave them a mature LVM (much better than the cut-down version of Veritas that Microsoft shipped).
      The main benefit I see today is that it allows multiple vendors to be hooked up to the same host with less vendor specific software required and thus less risk of fingerpointing.

  4. Roger The Viking :-) says:

    Hey Anthony,

    can you add a detailed section on DMP and Linux as well ?
    Would be good to know that HAK detect DMP on linux as well, and what HAK is changing in sych situatiuon

    regards from the snow

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