Finally! I got my second SATA drive up and running and partitioned and visible to ESXi. I created a 15G datastore on the unused partition of the disk. It’s 15G because I have a 16G USB stick which formats to just over 15G. The cunning plan is to dd the datastore to the USB stick to fool the hypervisor.

But, first things first. At the moment I have two USB sticks plugged in: the one used to boot ESXi and one newly FAT32 formatted. From ESXi’s busybox I can see the one I boot from, but not the other.

An extract from fdisk -l shows my boot “disk”:

Disk /dev/disks/mpx.vmhba33:C0:T0:L0: 1988 MB, 1988100096 bytes
64 heads, 32 sectors/track, 1896 cylinders
Units = cylinders of 2048 * 512 = 1048576 bytes

Device Boot      Start         End      Blocks  Id System
/dev/disks/mpx.vmhba33:C0:T0:L0p1             5       900    917504    5  Extended
/dev/disks/mpx.vmhba33:C0:T0:L0p4   *         1         4      4080    4  FAT16 <32M
/dev/disks/mpx.vmhba33:C0:T0:L0p5             5       254    255984    6  FAT16
/dev/disks/mpx.vmhba33:C0:T0:L0p6           255       504    255984    6  FAT16
/dev/disks/mpx.vmhba33:C0:T0:L0p7           505       614    112624   fc  VMKcore
/dev/disks/mpx.vmhba33:C0:T0:L0p8           615       900    292848    6  FAT16

Partition table entries are not in disk order

But I should also be able to see mpx.vmhba32.

This is certainly recognised by ESXi when booting as there are multiple references to it in /var/log/messages. There’s a lot of interesting looking usb messages in the log file but the one I see which is causing my current problem I believe is the following:

Aug 29 20:57:05 vmkernel: 0:00:00:31.460 cpu3:5590)<6>usb passthrough enabled; all eligible devices will be unclaimed by kernel drivers except for ESXi boot device vmhba33
Aug 29 20:57:05 vmkernel: 0:00:00:31.460 cpu1:4370)<6>usb-storage 2-1.2:1.0: unclaiming vmhba32
Aug 29 20:57:05 vmkernel: 0:00:00:31.460 cpu1:4370)usb storage warning (0 throttled) on unknown (SCSI cmd unknown): usb_stor_stop_transport called
Aug 29 20:57:05 vmkernel: 0:00:00:31.460 cpu1:4370)WARNING: LinScsiLLD: scsi_remove_host: Removing Host Adapter vmhba32
Aug 29 20:57:05 vmkernel: 0:00:00:31.460 cpu1:4370)ScsiPath: 4100: DeletePath : adapter=vmhba32, channel=0, target=0, lun=0
Aug 29 20:57:05 vmkernel: 0:00:00:31.460 cpu1:4370)WARNING: NMP: nmpUnclaimPath: Physical path "vmhba32:C0:T0:L0" is the last path to NMP device "Unregistered Device". The device has been unregistered.

So I guess my next mission is to find out how to disable the unclaiming. In the meantime I might use Linux to copy the datastore to the USB stick and see what happens then.