Yellow Bricks

by Duncan Epping

Fiddling around with SRM’s Storage Replication Adapter – Part II

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** Disclaimer: This is for educational purposes, please don’t implement this in your production environment as it is not supported! **

After my article this week about (ab) using the SRA provided through Site Recovery Manager to fail-over any LUN I expected some people reaching out to me with additional questions. One of the questions which came in more than once was “is it possible to do a test-failover of a LUN which is not managed by the SRM infra”? I guess the short answer is yes it is. The long answer is: well it depends on what your definition of a “test-failover” is. Of course booting up a physical machine from SAN while keeping the same IP etc would cause conflicts. I am also not going to show you how to re’ip your physical machines as I expect you to know this. From an SRM perspective how exciting is this?

To be honest, not really. The same concept applies. For a test-failover SRM calls the SRA by a script called “command.pl” and it feeds it XML. The following lines of XML are relevant for this exercise, but the critical one is “TestFailoverStartParameters”:

--> <TestFailoverStartParameters>
--> <ArrayId>BB005056AE32820000-server_2</ArrayId>
--> <AccessGroups>
--> <AccessGroup id="domain-c7">
--> <Initiator type="iSCSI" id="iqn.1998-01.com.vmware:localhost-11616041"/>
--> <Initiator type="iSCSI" id="iqn.1998-01.com.vmware:localhost-4a15366e"/>
--> <Initiator type="NFS" id="10.21.68.106"/>
--> <Initiator type="NFS" id="10.21.68.105"/>
--> </AccessGroup>
--> </AccessGroups>
--> <TargetDevices>
--> <TargetDevice key="fs14_T1_LUN1_BB005056AE32800000_fs10_T1_LUN1_BB005056AE32820000">
--> <AccessGroups>
--> <AccessGroup id="domain-c7"/>
--> </AccessGroups>
--> </TargetDevice>
--> </TargetDevices>
--> </TestFailoverStartParameters>
--> </Command>

Now in our case we want to fail-over a random non vSphere LUN. We will need the “initiator” (server(s)) who will need to see be able to see this LUN and we will need the LUN identifier. All of this can either be found in the SRM log files (LUN identifiers) or on the physical server (initiator details). If you would call command.pl and feed it the XML file the SRA will request the array to create a snapshot and give the host access to that snapshot. Now it is up to you to take the next steps!

It is no rocket science. Anything SRM does with the SRA you can do from the command line using command.pl and a custom XML file. As mentioned in the comments in my previous article, I know people are interested in using this for Physical Hosts… I will discuss this internally, but for now don’t come close, it is not supported!

 

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Comments

  2. Before people ask:

    The post contains all details needed to create your own custom XML file. As mentioned, check the SRM logs. They contain all the details of your specific environment. I cannot provide you with mine as it simply would not work.

    Do a fail-over, go to the log files and search for ““. There should be a full XML file there. Copy and past it in to a separate file and remove the “–> “. This file is what you will feed command.pl.

    Hope that helps,