virtual grind thoughts from the virtual world


Dell Compellent 6.4 Write Latency

Recently, I started seeing abnormal write latency across a number of pods in our environment. After spending a few hours looking at best practices and firmware on the compute and storage side, I decided to look at the switching layer. As expected, things like IO, buffers, buffer credits, etc. all looked fine.

Thinking it may be a cosmetic issue in Dell's Enterprise Manager, I engaged Compellent Support to have a look. After a week or so of analysis, I finally reached a senior engineer, who on a whim, asked me to test disabling SNMP at the controller level. In an instant, the abnormal write latency disappeared. What is alarming is that this was not just cosmetic, but actually felt all the way down to the host level.

I will say that I do not see this behavior in 6.3 but the change made a huge difference in and You can disable SNMP in Storage Center Manager by navigating to Storage Management -> System -> Access -> Configure SNMP Server, then click on "Stop Agent". If SNMP is not running, the link will say "Start Agent".

If you are running any FluidOS version 6.4.1 to 6.4.10, you may want to upgrade or disable SNMP and feel the difference!

Please note the change was made around 11AM, screenshots attached (click to view):

Controller View

Host View

Virtual Machine View


Reset Equallogic Member To Default Settings

In our lab environments, we are constantly using Equallogic members for various purposes. Sometimes, it is easier to simply reset an array and initialize it for quick use.

To reset an array to factory defaults, simply ssh in to the IP address of one of the network interfaces on your array and enter the reset command.

Reset this array to factory defaults? [n/DeleteAllMyDataNow] DeleteAllMyDataNow

Note that the array makes sure you want to reset the configuration by making you type in "DeleteAllMyDataNow".


Quickly Reset Equallogic Group Membership Password

I have run in to situations where I need to add new Equallogic members to groups that did not have the password documented. On an initial group configuration, settings such as group IP, grpadmin password, and membership password are chosen. Unfortunately, there is not an easy way to recover or see the membership password via the Group Manager.

Anyway, you can safely change the password to something new and NOT affect any existing settings to get a new member in.

To do this, simply ssh in to your group IP, and issue the grpparams and passwd commands:

Password for adding members: 1234
Retype password: 1234
Password change succeeded.


Restarting DRAC Interface

I recently ran in to a few situations where the DRAC web interface was acting funny.

In one event, when I would log in to the DRAC web interface, despite having the correct username and password, the web interface would just bring me back to the main login page. The second scenario would let me in the main DRAC admin page, but I could not launch a remote console.

Anyway, there is a very simple fix. Simply ssh into your DRAC ip address with the same username and password you use to access the web interface. Once you ssh in, you will be at the main DRAC admin prompt. To reset DRAC and NOT lose any settings, simply enter the command:

racadm racreset soft


Restarting the Equallogic Group Manager Interface

I have run in to a few occasions over the last couple of years where the Equallogic Group Manager interface stops responding. Usually, the statistics will start to fail or the login page is simply inaccessible.

To remedy this, you can restart the UI, with the following command via the CLI:

eqlinit restart-snap netmgtd

Please note that this does not restart your array, just the management interface.


Dell Hooks Server Tools Into VMware vCenter

Awesome new plugin from Dell, great to see more hardware vendors plugging in to VCenter.

Check it out here.


Dell Management Plug-In for VMware vCenter

Dell recently released their new Management plugin for VCenter. This is a great tool for an environment that is using Dell servers, as I do.

Some of the features I particularly like are:

  • Template based server provisioning
  • Workflows for provisioning servers
  • BIOS updates via VCenter
  • Virtual Appliance based deployment

It is very exciting to see all the vendors placing data center features in "off the shelf" applications for all types of users.

To read more about the product, check it out here.

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