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| author | David Edmondson <david.edmondson@oracle.com> | 2020-02-05 11:02:48 +0000 |
|---|---|---|
| committer | Max Reitz <mreitz@redhat.com> | 2020-02-20 16:43:42 +0100 |
| commit | 168468fe19c872d31d17581e6a6cf7b69bd105b1 (patch) | |
| tree | 08c88e95d9c9797002d96c97e59bd33e9dd970da /docs/interop | |
| parent | facda5443f5a8676fb635b82ac1046ac6b6a67ce (diff) | |
qemu-img: Add --target-is-zero to convert
In many cases the target of a convert operation is a newly provisioned
target that the user knows is blank (reads as zero). In this situation
there is no requirement for qemu-img to wastefully zero out the entire
device.
Add a new option, --target-is-zero, allowing the user to indicate that
an existing target device will return zeros for all reads.
Signed-off-by: David Edmondson <david.edmondson@oracle.com>
Message-Id: <20200205110248.2009589-2-david.edmondson@oracle.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
Diffstat (limited to 'docs/interop')
| -rw-r--r-- | docs/interop/qemu-img.rst | 9 |
1 files changed, 8 insertions, 1 deletions
diff --git a/docs/interop/qemu-img.rst b/docs/interop/qemu-img.rst index 42e4451db4..5f40137c10 100644 --- a/docs/interop/qemu-img.rst +++ b/docs/interop/qemu-img.rst @@ -214,6 +214,13 @@ Parameters to convert subcommand: will still be printed. Areas that cannot be read from the source will be treated as containing only zeroes. +.. option:: --target-is-zero + + Assume that reading the destination image will always return + zeros. This parameter is mutually exclusive with a destination image + that has a backing file. It is required to also use the ``-n`` + parameter to skip image creation. + Parameters to dd subcommand: .. program:: qemu-img-dd @@ -366,7 +373,7 @@ Command description: 4 Error on reading data -.. option:: convert [--object OBJECTDEF] [--image-opts] [--target-image-opts] [-U] [-C] [-c] [-p] [-q] [-n] [-f FMT] [-t CACHE] [-T SRC_CACHE] [-O OUTPUT_FMT] [-B BACKING_FILE] [-o OPTIONS] [-l SNAPSHOT_PARAM] [-S SPARSE_SIZE] [-m NUM_COROUTINES] [-W] FILENAME [FILENAME2 [...]] OUTPUT_FILENAME +.. option:: convert [--object OBJECTDEF] [--image-opts] [--target-image-opts] [--target-is-zero] [-U] [-C] [-c] [-p] [-q] [-n] [-f FMT] [-t CACHE] [-T SRC_CACHE] [-O OUTPUT_FMT] [-B BACKING_FILE] [-o OPTIONS] [-l SNAPSHOT_PARAM] [-S SPARSE_SIZE] [-m NUM_COROUTINES] [-W] FILENAME [FILENAME2 [...]] OUTPUT_FILENAME Convert the disk image *FILENAME* or a snapshot *SNAPSHOT_PARAM* to disk image *OUTPUT_FILENAME* using format *OUTPUT_FMT*. It can |