Experiences in the Home Lab With Micron P420m PCIe SSD, Part 1

By Rob Peglar - 2015-04-20

Greetings all! I’m delighted to have this opportunity to blog a bit about something I value, and that is a home lab.  Yes, even though I’m an executive at Micron, I’m an engineer at heart and believe strongly that, in this industry, we must keep our technical skills sharp by doing hands-on work. 

Those of you that know me well know that I’ve had a home lab since 1982—and for those of you that don’t, yes that date is accurate! I’ve had a home lab for 33 years now.  If you don’t believe me, just ask my wife about the extra AC circuits dedicated to the lab in our basement in three different houses over those 33 years!

But I digress. Let’s talk about running Micron’s P420m PCIe SSD in a VMware 6.0 ESXi environment.  I won’t bother describing the drive itself—there are all sorts of public reviews, blogs, and papers available about the drive.  But I do want to share my experience with you, and I hope that it encourages you to run one (or more) tests in your own home lab.

P420m SSD in VMware 6.0 ESXi Test

The server I used as a test unit is a 4-core Intel® i5-3340 with Crucial’s 32GB, 1600 MHz DDR3 RAM and their 250GB BX100 SSD as a boot drive.  I started with that configuration and then added the P420m. Here’s a screenshot showing the output (using my Mac with PuTTY to connect to the server) from the command “esxcli storage core device list”:

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Notice the size listed is 667,711MB, which is the base-2 representation of the available capacity on my P420m.  (There’s a P420m drive twice its capacity available—but I’m using the smaller one in the home lab.)

Also worth noting above is the default queue depth—notice it’s 255 instead of some lower figure.  This is an “out-of-box” benefit. Many drives have a much lower default queue depth, which requires tuning to perform well, if they are tunable at all.  The P420m performs very well without having to adjust the queue depth on the drive.  This is important in VMware environments.

Next, here is the screenshot from the ‘esxcfg-scsidevs’ command.  Note, I had already put the rather long device name string in a local file called /scratch/p420m, so it was handy to use “cat” on that file instead of typing in the whole thing.  Ah yes, “cat scratch” pun intended!

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Next, I installed the .vib file for the Real SSD Manager (RSSDM) utility, which  Micron provides for the P420m; it’s a handy tool for device-specific settings, logs, etc.  I used “esxcli software vib install” to install it.  The utility is installed by default in the directory /opt/micron/bin.  (The very last part of the command is cropped out of the picture below; it’s “—maintenance-mode.”)

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After that, I wanted to know how RSSDM viewed my new drive.  Here’s the output from “rssdm –L”, or “list”:

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Last, I ran the command “rssdm –S”, which retrieves the most important “SMART” instrumentation/counters.  This information is really valuable while the drive is being used in production—but it’s also quite helpful in the home lab to see what the drive itself is recording.

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For an SSD like the P420m, several key counters are listed, including failure counts, ECC corrections, and percentage lifetime used—all are really important to understand memory wear over the life of the drive.

That concludes my initial tour of the P420M in my home lab. In my next post, I’ll describe some of the workload testing I ran against the drive—and as a teaser, the results are excellent!  Stay tuned!

Rob Peglar

Rob Peglar