Yellow Bricks

by Duncan Epping

BC-DR

SRM Failback?

· ·

I get this question a lot:Does SRM have Failback capabilities? The answer is short but not simple, yes it does. Keep in mind that there’s no big red button labeled “Failback” which is the “not simple” part of the answer. Luckily for us the VMware Uptime Blog Team wrote an extensive article on how to do a failback with the current version of Site Recovery Manager. In short this is what one needs to do to failback:

  1. Reverse the replication direction in the storage layer to be from Site B to Site A
  2. Clean up the shadow virtual machines and protection groups on Site A
  3. Clean up the Recovery Plans configured on Site B
  4. Configure the protection group(s) on Site B
  5. Configure the Recovery Plans on Site A
  6. Test recovery from Site B to Site A
  7. Perform the recovery from Site B to Site A

Read the complete article on the Uptime Blog for all the details and show the article to your manager. It includes a table with an the estimated amount of time a failback would normally take manual vs SRM.

EMC SRDF Storage Replication Adapter

· ·

I was delivering a Site Recovery Manager Jumpstart today. During the configuration of the Storage Replication Adapter(SRA) the task got stuck at 23%. I’ve seen the configuration of the SRA get stuck once before at 23% so I knew it was the “DiscoverLuns” command that failed for one reason or the other.

We ran the configuration of the SRA again and it stopped after exactly five minutes. We decided to run the DiscoverLuns task again but this time manual with use of command.pl and a xml file as input. If you read the previous article on DiscoverLuns you know how to feed command.pl with the xml file and what info the file should contain.

Running the DiscoverLuns manually worked great, but it actually took little over 15 minutes to complete before the complete results were returned by the EMC DMX3. During the configuration via the GUI the task failed after exactly 5 minutes, so it seemed to time-out. Opening up vmware-dr.xml, which can be found in the Site Recovery Manager installation folder, revealed a time out of 300 seconds:

<CommandTimeout>300</CommandTimeout>

We changed the value to 1800, restarted the SRM service and reconfigured the SRA successful.

Storage Replication Adapter: discoverLuns…

· ·

Today I was implementing Site Recovery Manager with a colleague(Thanks Andy!!). During the configuration of the HP EVA SRA(Storage Replication Adapter) we received the following error:

discoverLuns script failed to execute properly

The error indicates that that the first part of the SRA configuration “discoverArrays” worked but when discovering the LUN’s and it’s replica’s it bailed out(23%). So after checking the config files and log files we decided to run the scriptfile, that the SRA uses, manually and see what happens.

First we created an XML file which feeds the script. The XML file contained the following, which can be copied from the SRM Log files:

<?xml version=”1.0″ encoding=”ISO-8859-1″?>
<Command>
<Name>discoverLuns</Name>
<ConnectSpec>
<Name>HP StorageWorks EVA Virtualization Adapter</Name>
<Address>san.yellow-bricks.com</Address>
<Username>user</Username>
<Password>password</Password>
</ConnectSpec>
<ArrayId>YB-SAN-01</ArrayId>
<OutputFile>C:\TEMP\SAN.Log</OutputFile>
<LogLevel>trivia</LogLevel>
</Command>

Now we were able to run the script with the XML file as input:

perl command.pl < file.xml

In our case running the script manually with the XML file as input didn’t return an error. This gave us the idea that it might be account or permissions related. During the configuration of the SRA we entered domain credentials, which were the same as the account being used during the manual run of the script. So it wasn’t the SRA account that was causing these problems.

After diving into the configuration we stumbled upon the SRM Service. The SRM service was started with a Local System account. We decided to change the account used for the Service from “Local” to a domain account… and indeed problem solved.

One would expect this to be part of the SRA documentation, but it isn’t. We contacted VMware Support and they had the same configuration running in their test environment except for the fact that they weren’t using AD authentication. In their case the Local System account just worked fine.

I’ve emailed Support all the log files and according to them our suspicion was correct. It seems to be related to the HP EVA SRA. The HP SRA seems to use the wrong account for authentication at one point during the script. Next up: Contact HP Support and let’s see if they can a) fix this or b) update their documentation.

How to use trusted certificates with SRM

· ·

When we were playing around with Site Recovery Manager last week we had the opportunity to ask a bunch of questions to Lee Dilworth. Lee is a Specialist System Engineer for Site Recovery Manager. During the discussion Lee told us about a document that Horst Mundt, also a VMware employee, wrote about using trusted certificates. We received the document via email and I wanted to share this with you. After a quick search on the internet I noticed that Horst already uploaded his document to VI:OPS:

SRM establishes a secure connection between the protected and the recovery site.

There are two options for authentication: Credential based or certificate based.

If you install SRM into an existing environment, make sure to choose the method that is appropriate for your environment.

If you have not changed the default certificates that were installed by the VMware vCenter server setup then go for credential based authentication. You do not need to read the this document.

If you have installed SSL certificates issued by a trusted CA on your VMware vCenter servers then go for certificate based authentication. The document explains how certificates need to be setup in order for this to work.

Site Recovery Manager and MSCS

· ·

When reading several SRM docs I was wondering if Microsoft Clustering was supported or not. I knew that in version 1.0 it wasn’t supported. When reading the Release Notes I noticed the following:

Full Support for RDM devices
SRM now provides full support for virtual machines that use raw disk mapping (RDM) devices. This enables support of several new configurations, including Microsoft Cluster Server. (Virtual machine templates cannot use RDM devices.)

Microsoft Clustering Services is supported as of Update 1. But you will need to keep in mind when creating your Recovery Plan that all nodes of the cluster will belong to the same Protection Group and can possibly  be started up or shutdown at the same time….. I haven’t configured SRM in combination with MSCS so far, if any of you has any tips/tricks let me know.