Matching EMC LUNs to Windows Disks

We are doing some SAN performance testing on the latest EMC VMAX array. As part of this, we are testing different storage configurations and policies and doing some baselining. I recently requested a set on LUNs for a new SQL install from my storage admin–I didn’t think about it, but I asked for disks that were the same exact size (200 GB) for both my data files and transaction logs. These disks were under different policies–so I had to identify them, which would prove difficult.

Windows storage manager shows me this picture of the disks assigned (note this pic is post fact–the disks have been configured):

EMC PowerPath shows us the following view:

As you can see we have two sets of disk numbers, and the numbers in PowerPath <> the numbers in Windows. One would think if someone looked under properties of the disk in Windows, you could find the underlying information. Unfortunately, they aren’t there. Enter the INQ utility, from EMC. It’s available via public FTP here.

You will run this utility from DOS, and use the following flag inq -showvol -sym_wwn. It will show the physical drive (which is the Windows number) and the EMC Device #–which is available in PowerPath. It’s still an ugly manual process, but it gets us the data.

Hopefully there are some PowerShell cmdlets for this info from EMC in a coming release of PowerPath.

 

 

 

 

About jdanton1
A DBA, cyclist, cook (who likes to play chef occasionally)

4 Responses to Matching EMC LUNs to Windows Disks

  1. meena270 says:

    Thanks for the information, do you know if the should be local to the server or it can do the remote as well?

  2. Allan Clark says:

    Thanks for the article, and for sharing! Related work posted at http://www.virtualinstruments.com/ipm-blog/howto/use-lun-nicknames-in-virtualwisdom-to-identify-vlun-symmdevice-names/ — but it’s geared towards making nicknames for the LUNs so that the user doesn’t have to manually look things up.

    As the author of the related work — written after-the-fact based on data captured during the issue — I worry about accuracy and re-use. I also recall that it’s server-specific (as meena270 asks). Is there a way to get this from the storage-side?

  3. jdanton1 says:

    It is possible to see it from the SAN side (at least with EMC Unisphere), but it does require that host agents be installed.

  4. Geoff says:

    it seems EMC have moved INQ – not sure where it is found now.

    According to the EMC forums the powerpath disk number should correspond with the disk number in storage manager.
    https://community.emc.com/message/515793

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