Bookmark and Share

Recent Posts

Booting an LPAR from a USB Port

July 11, 2017

Have you booted LPARs from your USB ports? It was much easier than I thought it would be.

I had been a little worried after reading the intro to this article:

Note from the editor: There is limited USB support in AIX and only specific devices are supported. Other devices might work, but IBM does not support their usage. JFS2 file systems are not officially supported on USB devices, but you can try this at your own discretion.

I guess I should start from the beginning: Recently I was talking with someone who was having networking issues that prevented him from using his NIM server. He wanted to know if he could use a USB flash drive to install his LPAR instead. While this has been supported for quite a while (see here and here), I hadn't taken the time to mess with it.

From the explanations in these posts (here and here), it seemed easy enough, though. We had a test machine, so we gave it a try.

First, we used dynamic LPAR (DLPAR) to get the USB controller attached to this test LPAR. On this system the adapter came up as Universal Serial Bus UHC Spec. After we attached it and ran cfgmgr, we verified that the device was there (usbms0 is what we were interested in).

    # lsdev | grep -i usb
    usb0       Available       USB System Software
    usbhc0     Available 00-08 USB Host Controller (33103500)
    usbhc1     Available 00-09 USB Host Controller (33103500)
    usbhc2     Available 00-0a USB Enhanced Host Controller (3310e000)
    usbms0     Available 2.3   USB Mass Storage

Then we checked for a virtual CD or an .iso image that was mapped to this LPAR. No dice on either. So I decided to copy a physical DVD to the virtual media library and present that to the client LPAR:

    # lsdev | grep cd

Nothing came back, so in the VIO server I ran:

    mkvdev –fbo –vadapter vhost4

This set up the virtual optical device that was connected to the LPAR.

Then, with the physical CD loaded in the drive, I ran:

    mkvopt –name aix7disk1.iso –dev cd0 –ro

This created the .iso image in the /var/vio/VMLibrary filesystem.

After it finished copying from the physical CD, I was able to load it in the virtual CD using:

    loadopt –disk aix7disk1.iso –vtd vtopt6

(Note: vtopt6 was created earlier when I ran the mkvdev –fbo command.)

I was able to verify it was there by running:

    lsmap –vadapter vhost4

Once the .iso image was mounted in the virtual optical device, I was able to log into the client LPAR and run cfgmgr. That made the cd0 device appear. It was linked to the .iso image in the virtual optical device by virtue of the loadopt command we ran earlier.

    # cfgmgr
    # lsdev | grep cd
    cd0        Available      Virtual SCSI Optical Served by VIO Server

Now that the LPAR had the source DVD (the AIX 1 DVD loaded into /dev/cd0) and the USB device (/dev/usbms0), I was ready to run the dd command:

    # dd if=/dev/cd0 of=/dev/usbms0 bs=4096k
    1010+1 records in.
    1010+1 records out.

At this point, we were able to reboot the LPAR and go into SMS and get it to boot from USB. Booting took a bit longer than it would from a virtual optical device, but it still happened quickly enough.

This is a handy procedure if you need to load a VIO server onto a bare metal machine, for example. It's especially valuable to know if you either don't have an optical device or you're using a split back plane and your optical device is connected to the other VIO server.

So how many of you have done this? What else are you doing with your USB drives?

Posted July 11, 2017 | Permalink

Post a Comment

Note: Comments are moderated and will not appear until approved

comments powered by Disqus