Lost connectivity to HP microSD Enterprise USB Kit

In this blog post MicroSD card RAID 1 as VMware ESXi boot device I wrote about the HP dual-microSD card module. This small piece of hardware provides data redundancy through a mirrored RAID 1 configuration and you can use it as an ESXi boot device.

Unfortunately, there seems to be a lot of problems with version 001 and 002 of the product. A lot of readers complained in the comments about issues, and I experienced some unexpected problems, too:

“Configuration Issues | Lost connectivity to the device […] backing the boot filesystem /vmfs/devices/disks/mpx … As a result, host configuration changes will not be saved to persistent storage.”

It seems, that in some situations the host experiences an all path down scenario and lost the connectivity to the SD card.

The good news: as ESXi runs in memory once it is started, there is no problem with production and the host keeps on running. If you want to get rid of the issue you just have to shut down the host and start it again. But this can only be a workaround.


If you experience the issue, too I recommend you to open a case with HP. There seems to be a problem with version 001 and 002 of the device. Version 003 should be working without problems.

The latest version has another design, so they are easy to distinguish. The version is imprinted on the stick, just search for the product number:


  1. Pingback: MicroSD card RAID 1 as VMware ESXi boot device

  2. Tom

    Is the RAID1 in this device hardware-based, implemented in the USB device itself??
    Or is the RAID1 software-based, implemented in the microSD cards??
    Please clarify if you can.
    Thank you, Tom

  3. Andreas

    Hi Tom,

    you are right, the RAID1 is implemented in the USB device itself. With the new version 003 USB kits the solution works as expected.

  4. Stiffler

    I have found a statement from hpe.

    They replace the old raid stick with the new one.


    To correct this issue, replace the HP Dual 8GB microSD Enterprise Midline USB Kit using the following Proactive Customer Care (PCC) program:
    An HPE Dual 8GB microSD EM USB Kit with Part Number 741281-003 will be provided at no charge.

  5. Tom

    Hi Andreas,
    Thank you for explaining about the RAID being implemented in the hardware.
    This should make it possible to install non-HP faster 32 GB sdMicro cards for less $$$$.
    Which avoids having to keep the logs on a datastore.
    Thank you, Tom

Leave a Comment

Your email address will not be published. Required fields are marked *