When the LDoms product was first released a very annoying problem was that the format(1m) command was not working in a guest domain with virtual disks. So when one wants to change the partioning of a virtual disk, he has to use the fmthard(1m) command which is not a very user friendly command.

The good news is that bug 6531557 (format(1m) does not work with virtual disks) has just been fixed into Solaris Nevada and Open Solaris. So the format(1m) command now works with virtual disks in a LDoms guest domain. The fix of that problem for Solaris 10 should come later as a patch.

Note that there are some format(1m) sub-commands will still not work because such commands only work with SCSI disks and virtual disks do not currently appear as SCSI disks (even when a virtual disk is created from a physical SCSI disk).

The following shows which format(1m) sub-commands work with virtual disks and which do not:

FORMAT MENU:
        disk       - select a disk
        type       - select (define) a disk type
        partition  - select (define) a partition table
        current    - describe the current disk
        format     - format and analyze the disk
        repair     - repair a defective sector
        label      - write label to the disk
        analyze    - surface analysis
        defect     - defect list management
        backup     - search for backup labels
        verify     - read and display labels
        save       - save new disk/partition definitions
        inquiry    - show vendor, product and revision
        volname    - set 8-character volume name
        !<cmd>     - execute <cmd>, then return
        quit

Commands in green work with virtual disks.
Commands in red do not work with virtual disks.

Another good news is that this also fixes some underlying problems such as doing I/O using an absolute disk offset, or providing the correct virtual disk size. These problems were not impacting the end-user but they were causing troubles to developers such as Dave Miller and Fabio who working hard to have Linux running with LDoms.

Although this fix does not solve all problems Dave and Fabio are facing, it introduces the foundation for a next fix which hopefully should solve everything by introducing the support for unformatted disk (bug 6575050) and this will avoid the hacks currently required to be able to use a Linux disk image.