Announcing vmfs-tools version 0.1.0

Apart from having been on vacation under the sun, I've been busy working with a friend of mine on something we called vmfs-tools, which is partly why there is still no part 2 to the previous post.

In case you don't know, VMFS is a clustered filesystem designed to store virtual machine disks for VMware ESX or ESXi Server hosts. Our ultimate goal is to give read-write access to these filesystems from some other host, for maintenance tasks such as, e.g. backup.

Files within the VMFS file systems can be accessed either from a CLI tool, or through a FUSE filesystem.

For the moment, only read support is available, and some known issues are still to be fixed, as well as a revamp of a part of the internal API.

The (quite sparse) homepage for this project is hosted here.

A Debian package is also sitting in NEW.

2009-05-24 20:55:53+0900


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5 Responses to “Announcing vmfs-tools version 0.1.0”

  1. Brien Says:

    This would be a very nice replacement for VCB dumping and then doing the loopback offset mount hack. I guess getting to the VMFS is the first step, and then seeing if we can mount the snapshot file to perform the backup. VMware is going to love that potentially naughty systems can now access the VMFS :-)

  2. Tommy Says:

    Can anyone tell me what the offset should be on my loopback device?

    I’ve created a 512MB file with dd, connected it via iSCSI to my ESXi server, created the VMFS and put up some test files.

    If i try directly on the file:
    nas:~# vmfs-fuse /mnt/iscsi.img
    VMFS VolInfo: invalid magic number 0x00000000
    VMFS: Unable to read volume information
    Unable to open device/file “/mnt/iscsi.img”.

    This obviously doesn’t work. Then I tried to create a loopback device, but i don’t know the offset.

    losetup -o ???? -r /dev/loop1 /mnt/iscsi.img

    Can anyone help me here?

    Thank you in advance. :)

  3. chris Says:

    Hi Tommy,

    Try with offset=65536

  4. glandium Says:

    Tommy, if you’re using a 2.6.x linux kernel, you can setup a loopback device with losetup and then use kpartx (from multipath-tools) to get devices mapping the partitions in the loopback device.

  5. Tommy Says:

    Hi glandium,

    It worked! Thank you for explaining it for me.

    For reference to others:
    nas:~# modprobe fuse
    nas:~# losetup -r /dev/loop0 /mnt/iscsi.img
    nas:~# kpartx -a -v /dev/loop0
    nas:~# vmfs-fuse /dev/mapper/loop0p1 /mnt/iscsi/