Showing posts from January, 2017

Using PowerCLI to get a Datastore from an NAA ID

This is just a quickie (mainly for my own notes in the future): if you ever need an easy way to figure out which datastore is being referenced by a given naa number (like if you're troubleshooting datastore access issues and the logs all reference that ID type), you can use this command to search it out:

get-datastore | ? {$_.ExtensionData.Info.Vmfs.Extent.Diskname -match "NAA NUMBER"}

Creating VICredentialStore Items without Typing Your Password into the Command Line

I use PowerCLI a lot.  Like, when VMware said to stop using the C# client, I just started using PowerCLI instead of learning the Flash based web client.  As such, I log into many vCenter servers many times each day, and creating a VICredentialStore item for each vCenter that I use is one trick that saves me a lot of typing and therefore time.

The New-VICredentialStoreItem cmdlet is super easy to use, which creates these credential store items.  Once you have an item created, those credentials get used automatically when you connect to a vCenter server, making the logon faster and easier.  To use it, just follow this syntax:

New-VICredentialStoreItem -Host vCenterServer -User JColeman -Password SuperSecretPassword

And there you go, next time you use connect-viserver vCenterServer, it will automatically pass JColeman as the username and SuperSecretPassword as the password.

Of course, no one ever wants to do this.  Who in their right mind would want to type their password, in plain text…

Extreme IO Latency Caused by a Poorly Seated Fiber Cable

One of my customers was experiencing some extreme IO latency in their environment: in the hundreds of ms.  Obviously, there was some pain associated with this issue, and so they asked for help.  This environment had 3 HP c7000 chassis and 2 different SANs; the issue was affecting every host accessing every LUN, so we decided that the issue must be in the fiber channel fabric somewhere.

After poking around, we quickly realized that the firmware on the Brocade switches was from January 2013, so was quite old.  I pulled up top on each switch and saw no appreciable CPU or Memory usage.  Next, I looked at porterrshow to see if there were any problems on the switches; each one had a single port that had a ridiculous number of Enc Out errors.  I cleared the error stat counters by using portstatsclear -i 0-33 and then issued another porterrshow, and found that we had roughly 100,000 Enc Out errors on that port each second.  Coincidentally, each switch had 1 port that was displaying this issue…