Tag Archives: multipathing

EqualLogic Multipathing Extension Module – Installing

Last year I wrote a post on an issue attempting to install the DELL EqualLogic Multipathing Extension Module using VMware Update Manager.  I discussed an alternative method to VUM using the CLI to install the MEM.  The post has turned out to be fairly popular.  I’m guessing though that most people are more interested in how to install the EqualLogic MEM using VUM rather than my original workaround.  So I thought I would run through the steps using a version of MEM that now works.  The whole process of importing, attaching, and remediating came out a little longer than expected but I managed to capture all the steps in what I think is fairly easy to follow.

The version of MEM I am using is 1.1.2 (released Dec 2012).  You can obtain it from the EqualLogic support site (sign-in required).  The release notes state that the only change from version 1.1.1 is that it’s now compatible with Update Manager 5.1.  EqualLogic also state that if version 1.1.1 is installed 1.1.2 is not required.  At least this now explains why I had trouble with VUM and version 1.1.1

Using the vSphere Client under Solutions and Applications select Update Manager and click on the Patch Repository tab.

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Click on Import Patches.  Browse to the location of the patch.  Select the version you want.  In my case for ESX5

*Note: The ZIP file from the EqualLogic support site needs to be extracted prior to importing.  Once extracted there will be two zip versions.  An ESX4 and an ESX5 version.

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If the Upload is successful you’ll then be asked to confirm the Import.

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Once imported scroll to the bottom of the repository list and you should see the new Host Extension.

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With the extension imported into Update Manager we now create a new Baseline.  Click on the Baselines and Groups tab.

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Click on Create to create a  new baseline.  Assign a name to the baseline and a description.  For the Baseline Type select Host Extension and click Next.

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Scroll to the bottom of the list and select the recently imported MEM patch.  Click the down arrow to Add the Extension and click Next.

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Confirm that the correct extension was selected and click Finish to create the baseline.

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With the patch imported and a new Baseline created for the Extension we now have to Attach the baseline.  This can be done at the top of the vCenter level or right down to the Host level.  In this case I just want to do a single host.  So I’m going to select the host and then select the Update Manager tab.  I’m then going to click Attach.

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Select the newly created baseline and click Attach.

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The baseline will now appear with a Question Mark beside it until a new scan is performed.  Click Scan, make sure Patches and Extension are selected and click Scan again.

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Once the scan is complete the Extension will now show up with a red cross signifying that it’s missing and needs to be Remediated.

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Click the Remediate button to start the process.  Select Extension Baselines on the left and the recently created Baseline on the right.  Then click Next.

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Omitted is a number of steps from the Remediate Wizard.  The options revolve around how the host and cluster will behave in Maintenance Mode.  The options are fairly straight-forward and the default options usually suffice. The last screen will summarise the options selected.  Make note what options have been selected and that the correct Baseline is selected.  Click Finish to start the Remediation.

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The host will now enter Maintenance Mode using the options you selected above.  Once complete we can select a datastore and select pathing where we can see a new pathing option and it’s selected by default. We will also see that all paths to the LUN are Active.

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The whole importing and creating a baseline can seem a little tedious at first, but once done, all that’s needed is a scan and remediate on new hosts.

References

Link to original article EqualLogic MultiPathing Extension Module -- Alternative Install

Download the latest Extension module from EqualLogic Support Site

EqualLogic MultiPathing Extension Module – Alternative Install

UPDATE: If you’re looking for step-by-step instructions to install the EqualLogic Multipathing Extension Module click HERE to go to my most recent post on the topic.  

UPDATE: Note that the ESXCLI command below  —depot has a double dash.

I recently ran into an issue where vSphere 5.1 Update Manager scans and detects the latest Dell EqualLogic Multipathing Extension Module 1.1.1 as Not Applicable for ESXi 5.1 and will not select the patch during a Remediate.  Below I show how to install this extension via the ESXCLI.

If you’re running a DELL EqualLogic SAN with ESX you should be running DELL’s Multipathing Extension Module (MEM).  MEM is a Path Selection Plugin (PSP) driver for ESX.  In fact no matter what SAN you have you should investigate if they have a PSP driver for ESX.

ESX have three built-in pathing options, (Most Recently Used, Round Robin, and Fixed).  By installing EqualLogic’s MEM you get a fourth option called DELL_PSP_EQL_ROUTED.  EqualLogic PS Series SANs can run Active / Active pathing.  By installing the MEM, ESX can be made aware of this and can load balance appropriately.  This can all lead to increase in bandwidth utilisation and lower network latency.

Since ESX4 I’ve been installing the EqualLogic MEM using VMware Update Manager through the vCenter C# client.  I’ve never had any issues right up until and including ESXi 5 Update1.  The process is quite simple.

  1. Import the MEM as a patch.
  2. Create a new Baseline with a Host Extension and add the MEM extension that was imported. (EqualLogic have different versions for each ESX version so be mindful).
  3. Attach the baseline to the Host
  4. Perform a Scan and Remediate the ESX host.
  5. Reboot.

As mentioned in the beginning, Update Manager 5.1 saw the patch at Not Applicable.  I took this as an opportunity to try and install the patch through the ESXCLI.  To do this I used VMA.  If you’re not running or haven’t tried the VMware Management Assistant (VMA) it’s worth looking into.  It’s a nice convenient way to get CLI access to all your ESX hosts.

To install a PSP driver the host needs to be in Maintenance Mode.  So do this first or you’ll get a similar error to below.

Next transfer the EqualLogic Multipathing files to a location on the ESX host you want to install to.  In my case below I installed them to a folder on datastore1.

Back on the VMA use the ESXCLI and enter the following command, substituting the file location for your own, to install.

Esxcli —server=my_esx_host.domain software vib install —depot /vmfs/volumes/datastore1/EqualLogic-ESX-Multipathing-Module/dell-eql-mem-esx5-1.1.1.270268.zip

This is a kernel driver and a reboot is required for the PSP driver to successfully apply.  Once a reboot is performed the new PSP becomes the default selection.

Now selecting a datastore and selecting pathing you can see a new pathing option and it’s selected by default.  You will also see that all paths to the LUN are Active.

Appendix

Most recent step-by-step MEM installation article EqualLogic Multipathing Extension Module – Installing

VM Windows Cluster Volumes Offline in ESX

Windows Clustering on physical hardware is a pain at the best of times.  Just getting it to work can sometimes be a little try and effort… with a whole lot of luck.  Getting clustering to work in VMware is just cruel.

So when tasked to create a VM of a physical Windows Cluster for a test environment, boy was I excited! {Sarcasm sign}.

Actually creating the VM within ESX wasn’t that difficult.  Using Converter I created a VM of the OS.  Then using our DELL EqualLogic SAN I made clone copies of the cluster volumes.  I presented those volumes with the newly created VM as RDMs.  The process seemed to work really well until.  The OS booted up.  I could see all my presented volumes.  Issues began when I tried to start the Clustering Service and take it out of manual mode.  Out of the 6 volumes I had only one would ever become Online while all the others would (after some time) fail.

I spent days working through the issue (I’m pretty sure this is why I’m balding).  Articles seemed to lead me to DISKPART and trying to change the SAN Online Policy, manually online the disk, changing the READONLY attribute.  None of these seemed to work.  I’m assuming because there was an attribute that said the disk was Clustered and would prevent me making any changes.  Still, I thought I was on the wrong ‘path’ and began looking into a lower level issue at the ESX level.

The crux of my issue turned out to be a iSCSI multipathing problem.  DELL EqualLogic SANs run in an Active / Active pathing method where I/O is sent over all paths.  DELL has a third party Storage API plugin for ESXi that change the default behaviour of how mutlipathing works.  This is normally a good thing but for Windows Clustering in ESX… this is bad.

The solution is fairly simple to resolve.  The steps below is a rough outline of how to identify and change the multipathing policy.

Using vSphere vCenter, the changes are made within the Storage Adaptor.  In this case it’s the iSCSI Software Adaptor under the Configuration tab.

In the bottom pane select the paths view.  Expand the Target column and identify one of the cluster volumes with issues.  In this example I have a Dead path due to a recently removed SAN volume which is safe to ignore.  The one below is of interest as it’s one of the clustered volumes.  Remember the Runtime Name in the left column.

Change to the Devices view and locate the Runtime Name.  Right click on this device and select Manage Paths.  In this example DELL_PSP_EQL_ROUTED was selected as default.  Changing this to Most Recently Used (VMware) sends I/O only ever down one path.  The change is immediate.  As my volumes are offline I can safely make the changes.  On a working production volume I wouldn’t be making path selection changes during business hours.

Back over on the Windows Cluster VM I can now restarted the Clustering Service and have it correctly Online all the volumes.

MSCS is quite in depth and not for the faint hearted or something configured before you end home for the night.  Virtualising MSCS requires additional planning and thought in addition to regular planning.

Appendix

VMware -- Setup for Failover Clustering and Microsoft Cluster Service