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Diffstat (limited to 'docs/tools')
| -rw-r--r-- | docs/tools/_templates/editpage.html | 5 | ||||
| -rw-r--r-- | docs/tools/qemu-img.rst | 31 |
2 files changed, 31 insertions, 5 deletions
diff --git a/docs/tools/_templates/editpage.html b/docs/tools/_templates/editpage.html deleted file mode 100644 index 2a9c8fc92b..0000000000 --- a/docs/tools/_templates/editpage.html +++ /dev/null @@ -1,5 +0,0 @@ -<div id="editpage"> - <ul> - <li><a href="https://gitlab.com/qemu-project/qemu/-/blob/master/docs/tools/{{pagename}}.rst">Page source</a></li> - </ul> -</div> diff --git a/docs/tools/qemu-img.rst b/docs/tools/qemu-img.rst index c9efcfaefc..cfe1147879 100644 --- a/docs/tools/qemu-img.rst +++ b/docs/tools/qemu-img.rst @@ -866,6 +866,37 @@ Supported image file formats: issue ``lsattr filename`` to check if the NOCOW flag is set or not (Capital 'C' is NOCOW flag). + ``data_file`` + Filename where all guest data will be stored. If this option is used, + the qcow2 file will only contain the image's metadata. + + Note: Data loss will occur if the given filename already exists when + using this option with ``qemu-img create`` since ``qemu-img`` will create + the data file anew, overwriting the file's original contents. To simply + update the reference to point to the given pre-existing file, use + ``qemu-img amend``. + + ``data_file_raw`` + If this option is set to ``on``, QEMU will always keep the external data + file consistent as a standalone read-only raw image. + + It does this by forwarding all write accesses to the qcow2 file through to + the raw data file, including their offsets. Therefore, data that is visible + on the qcow2 node (i.e., to the guest) at some offset is visible at the same + offset in the raw data file. This results in a read-only raw image. Writes + that bypass the qcow2 metadata may corrupt the qcow2 metadata because the + out-of-band writes may result in the metadata falling out of sync with the + raw image. + + If this option is ``off``, QEMU will use the data file to store data in an + arbitrary manner. The file’s content will not make sense without the + accompanying qcow2 metadata. Where data is written will have no relation to + its offset as seen by the guest, and some writes (specifically zero writes) + may not be forwarded to the data file at all, but will only be handled by + modifying qcow2 metadata. + + This option can only be enabled if ``data_file`` is set. + ``Other`` QEMU also supports various other image file formats for |