Status Update: Summary of the Week

Work done this week:

  1. Multi extents subformats support. The code is ready to handle multi extents disks (twoGbMaxExtent* formats)

  2. Investigated disk image formats on ESX Server 3.5 and 4.

    Downloaded and installed ESX servers on VM, created VM disks and analyzed their formats. The conclusion is that neither ESX Server has COWD sparse extent, it seems the format described in spec is not widely used nowadays. Although the vmdk driver now should support that type extent, but no real world image is seen so far for a test.

  3. Checking out VDDK. The Virtual Disk Development Kit provides library interface for everyday work on various VM disk formats, such as create/clone/read/write. And also a set of tools to manage or mount images. (The idea of mounting image disk as host OS block device seems a nice use case, could this possibly be done through a generic QEMU block driver? Qcow2 can be mounted with nbd: http://en.wikipedia.org/wiki/Qcow#Mounting_qcow2_images)

  4. Sparse extent compression support. The compression support is added by using zlib compress/uncompress interface. The code is already written but still need test.

gsoc
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