How to match an Windows (HyperV) disk to a SAN attached disk using the wwn

Hard Drive

Where do I find the wwn of a disk in Windows / HyperV? That’s the question.

There are a number of identifiers to find out which LUN is which disk, but the only undeniably unique number to find out which disk is which LUN is by using the globally unique wwn number of a LUN. The question is: “where can I find the wwn of a disk in HyperV?”

The LUN number, as assigned by the storage array can be found by using diskpart:

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How to list the naa-numbers of LUNs and VMware VMFSs on a Dell EMC Unity system

EMC Unity

In the Unity the naa numbers (wwn) are listed in the “block” section, but not in the VMware section. If you view the LUNs from the host perspective, the naa numbers are visible, but in the list of LUNs  would have been easier. You can list all details from LUNs and datastores on the CLI by using the uemcli commands:

uemcli -d 10.11.12.13 -u Local\admin -p [password] /stor/prov/luns/lun show -detail > unity.txt
uemcli -d 10.11.12.13 -u Local\admin -p [password] /stor/prov/vmware/vmfs show -detail >> unity.txt

Now simply open the unity.txt file and voila: there they are!

New Dell EMC Unity lineup: Unity XT 380F, 480F, 680F and 880F?

While looking for something totally different I stumbled on a few new Unity XT (?) model numbers.

On this dellemc.com website I spotted some Chinese publication on this new model.

[edit] The new and working website is now working: www.dellemc.com.

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Cisco MDS CLI commands when checking for defects or signal degradation

Cisco MDS

Checking the environment of a switch:

  • show environment temp = what are the temperatures of the intake(s) and outlet(s)
  • show environment power = are the PSUs still working fine?
  • show environment fan = are the fans still working fine?

Checking for errors and signal degradation

  • show interface fc1/10 counters = show all standard counters for port fc1/10
  • show interface fc1/10 counters details = show the detailed counters for port fc1/10
  • show interface counters = show all standard counters for all ports
  • show interface detail-counters = show the detailed counters for all ports
  • show interface detail-counters | i CRC = show the detailed counters for all ports which contain the text “CRC”
  • show interface transceiver calibrations = show the specs of all SFPs
  • show interface transceiver details = show the specs and power details of all SFPs
  • show interface transceiver details | i “x Power” = show the current Rx/Tx power of all SFPs

Common knowledges dictates that fiber optice patches need to be cleaned with proper equipment to prevent unnecessary signal loss. See this blog post for more details on how and why to keep optic cables clean.

How to enable a replica-LUN on Unity

EMC Unity

LUN-replication on Unity works slightly different than it previously did on VNX or even Clariion. In these older generations, when you deleted the mirrorview Mirror Group, both the primary and secondary LUNs became usable as separate entities.

In Unity the secondary LUN is a different beast. First of all: in Unity you can only set up replication from the primary Unity/LUN. The process on the source-Unity will create a LUN-replica and a replication session on both Unitys.

But what happens when you need hosts to access the secondary LUN? A failover works as designed and the previous secondary LUN becomes writable, but when you break the replication session, the replica-LUN has a flag that needs to be reset, but you’ll need the CLI to do that. This is how I did it:

  • In Unisphere I listed all LUNs and I made sure to include the “CLI ID” column
  • I noticed the ID of the LUN I need to grant access to is “res_56”
  • I started PUTTY and made sure logging to a file was configured so I could easily browse / search the possibly large amount of data some commands can produce, especially “-detail” commands tend to be very explicit
  • Log in as the “service” user to the Unity command line

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