VMware ESXi 4: SD Flash in BL460c G6

HP has incorporated an interesting option for running VMware ESXi 4 from flash.  Instead of using a USB stick, an SD card can simply be popped in the embedded reader.  While any SD card would work, HP emphasizes that only a specific model is fully supported — the ones I received are actually made by Lexar and the official nomenclature is: HP 4GB SD Flash Media, Part Number 580387-B21.

In my HP BladeSystem c7000 enclosure with BL460 G6 (Nehalem) blades, the SD slot is easily exposed by sliding each blade out of the chassis:

Once the SD flash card is in place, it is trivial to install VMware ESXi:

You may also be interested in articles from Rick Scherer and TechHead on this topic.

Hyper-V on Flash?

Sure, Hyper-V Server — but not Windows Server 2008 with Hyper-V — supports boot-from-flash when purchased from a server OEM, but to the best of my knowledge there are no vendors shipping such configurations at this time.  Note that Microsoft recommends a 16GB flash drive for Hyper-V Server deployment (compared to a slender 1GB for ESXi 4), but a PlayStation Portable is an acceptable substitute in a pinch.

Motivation

Two great reasons for running ESXi from flash:

  • Eliminate the need for local disks — lower power and cooling requirements
  • Provide dual-boot capabilities in a lab environment

Why would you run VMware ESXi from flash?


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18 comments

  1. Vladan’s avatar

    Nice….

    I’m really into those energy economy features …

    With 10 blades in the chassis those monthly(yearly) economies in power consumptions are for sure to re-think twice when you’re planning your infrastructure…

  2. Kevin Houston’s avatar

    Eric – thanks for bringing this feature to light. I’ve posted some deeper insight into both HP and Dell’s SSD offerings on my blog at http://BladesMadeSimple.com. (I made sure to reference your blog several times.)

    1. Eric Gray’s avatar

      Glad you liked it.

    2. brandon’s avatar

      Thats all great, etc, but HP recently released a critical advisory saying that the USB methods are apparently risky and can cause problems. I’m not at my usual work machine so I don’t have the advisories handy. They focus on the SD card method, which is great, but not for users who have already implemented one way on their blades, or frankly if they have G5 models (as my company does) compared to G6 models. So now I’m not supposed to use the internal usb method anymore, but I have this awesome SD card method which I can’t use at all since I don’t have the slot. HP really needs to announce that a replacement USB drive has been found that doesn’t have the problems of their original, or can ship me replacement blades. Either or.

      1. Kevin Houston’s avatar

        Brandon – do you have a link to the HP Critical Advisory you referenced?

        1. Collin C. MacMillan’s avatar

          Note that the HP CA implies the problem is due to port proximity to other functions and NOT the fact of running ESXi on USB flash. Key to this idea is this statement about a workaround:

          “Move the HP 4 GB USB Flash Media Key (Part Number 580385-B21) to an external USB port on the server. Ensure that the USB key does not interfere with closing the rear rack door.”

          Sound a lot like internal shielding to me :) Perhaps a better grade of USB key will be the fix. Of course, changing your ESXi settings to avoid post-boot I/O to the USB key could be another workaround if I/O driven interference is truly the cause…

          On the DL series, the problem is physical (doesn’t allow lid to close) so a low-profile flash will do the trick. Same proximity language with “possibility” of affect to “other electronic components” for this series too. Interesting that this did not show-up on testing at HP (flash vendor/model change in production?)

          If you have the SD slot – use it. Check the SD class ratings for better performance (2/4/6 MB/sec) which can affect boot times. If you’re logging to SD, try to find a class 6 card. We’ve been running ESXi from USB flash in the lab and in SMB’s since 3.5 without issues. It is especially handy for white box lab and laptop installs where on-board HD controller may not be supported.

        2. Brett Hayes’s avatar

          I have done the same items as you with great success. One question that I have is where have you configured the Scratch to point to? I have seem iSCSI / NAS connections for this but wondering if the SD Card can be used for this to keep it local. Thoughts?

        3. Jason T’s avatar

          I’m considering this on my DL360 G6 servers to eliminate the need for 1 (or 2 in RAID 1) 72GB SAS drives. A considerable amount of savings in purchase costs when you scale it up.

          That, and I love the look on people’s faces when they see a rack of servers with no hard drives – and all the lights are green. :)

          However, for now, I’m planning on purchasing an 8GB SD card for each of our existing servers to load up the VM Installation media for remote reinstallations. iLO remote media isn’t always as reliable as I would hope.

        4. Yassine Souabni’s avatar

          Hi,
          even when having small amount of servers dedicated to run hypervisor,
          the “diskless server” feature enabled by implementing ESXi on SD card or Usb stick
          is really intereting from the perspective of total disks cost.

          Example :
          for a 4 servers running hypervisor with each a couple of 146Gb 15k sas disks in Raid1
          you would have to pay about (8 x ~400$)
          -> about the price of a brand new BL360 additional blade + saving 1000$ !

          That said, my question is related to efficiency of this config when used
          in production to run several VM’s/host.

          SCSI is by far more speedy than USB ctrl or SD.
          So are there any I/O contraints to consider when using such solution ?
          Or I’m out of subject ?

          Thanks for any anwer.

          1. Eric Gray’s avatar

            The only tradeoff that I am aware of with USB flash is slightly longer boot time. After that, the USB flash is mostly out of the picture — everything is in memory.

          2. stkey’s avatar

            To use the SD card for installing VMWARE, do I just copy the .iso file onto the card? And then at boot pick that file and it will launch into the install script? This would be similar to using the USB port in the back of the Onboard Administrator.

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