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Forum Article: USB External Hard Drive on ESX Server

VMware - Using USB External Storage

How-to:
For most systems configured out of the box this is quite simple, however there are a few rules that need to be adhered to:

• When mounting FAT32 partitions in Windows, the maximum partition size allowed is 32GB. Don't ask why - it just is (sigh).
• NTFS partitions aren't writable by the COS, but are readable.
• USB 2.0 isn't supported by the COS (But USB 1.1 is) - USB 2 devices may generate errors, but will probably work.

In the first instance you should plug your USB storage device into the ESX host, wait a few seconds and type (Into the console or a putty session):

dmesg

You should see something like this (amongst some other messages):

hub.c: USB new device connect on bus1/3, assigned device number 2
usb.c: USB device 2 (vend/prod 0x4b4/0x6830) is not claimed by any active driver.
Initializing USB Mass Storage driver...
usb.c: registered new driver usb-storage
scsi2 : SCSI emulation for USB Mass Storage devices
  Vendor: ST340083  Model: 2A                Rev: 0000
  Type:   Direct-Access                      ANSI SCSI revision: 02
sda : INQUIRY EVPD failed.
status = 1, message = 00, host = 0, driver = 08
VMWARE: Unique Device attached as scsi disk sda at scsi2, channel 0, id 0, lun 0
Attached scsi disk sda at scsi2, channel 0, id 0, lun 0
scsi_register_host starting finish
SCSI device sda: 781422768 512-byte hdwr sectors (381554 MB)
 sda: sda1 sda2
scsi_register_host done with finish
WARNING: USB Mass Storage data integrity not assured
USB Mass Storage device found at 2
USB Mass Storage support registered.

If this isn't the case, maybe you need to start some drivers up:

insmod usbcore
insmod usb-storage
insmod usb-uhci

Create a mount point for each volume on the external storage that you want to mount. In this case I can see from above that I have sda1 & sda2 but I only want to mount the first (sda1):

md /mnt/usb

Mount the partition on the external storage:

mount /dev/sda1 /mnt/usb

That's it.

If you are unsure of the partitions on the external storage, you can have a look with:

fdisk -l /dev/sda

You can also create & delete partitions using fdisk if required:

fdisk /dev/sda

Follow the prompts from there.
When you have finished, don't forget to unmount the external storage before you unplug it!

cd /
umount /mnt/usb