Put the create options in alphabetical order, add compression_type and extended_l2, and also mention the common runtime options. I did not add rarely-used runtime options because I think it's too much information.
Signed-off-by: Stefan Hajnoczi <[email protected]> --- docs/system/qemu-block-drivers.rst.inc | 91 ++++++++++++++++++++------ 1 file changed, 70 insertions(+), 21 deletions(-) diff --git a/docs/system/qemu-block-drivers.rst.inc b/docs/system/qemu-block-drivers.rst.inc index ec9ebb2066..af72817763 100644 --- a/docs/system/qemu-block-drivers.rst.inc +++ b/docs/system/qemu-block-drivers.rst.inc @@ -59,13 +59,27 @@ options that are supported for it. .. option:: qcow2 QEMU image format, the most versatile format. Use it to have smaller - images (useful if your filesystem does not supports holes, for example - on Windows), zlib based compression and support of multiple VM + images (useful if your filesystem does not support holes, for example + on Windows), zlib/zstd compression and support of multiple VM snapshots. - Supported options: + Supported create options: .. program:: qcow2 + .. option:: backing_file + + File name of a base image (see ``create`` subcommand) + + .. option:: backing_fmt + + Image format of the base image + + .. option:: cluster_size + + Changes the qcow2 cluster size (must be between 512 and 2M). Smaller cluster + sizes can improve the image file size whereas larger cluster sizes generally + provide better performance. + .. option:: compat Determines the qcow2 version to use. ``compat=0.10`` uses the @@ -74,13 +88,9 @@ options that are supported for it. newer understand (this is the default). Amongst others, this includes zero clusters, which allow efficient copy-on-read for sparse images. - .. option:: backing_file + .. option:: compression_type - File name of a base image (see ``create`` subcommand) - - .. option:: backing_fmt - - Image format of the base image + Selects the compression algorithm (zlib or zstd). .. option:: encryption @@ -150,19 +160,11 @@ options that are supported for it. Amount of time, in milliseconds, to use for PBKDF algorithm per key slot. Defaults to ``2000``. Only used when ``encrypt.format=luks``. - .. option:: cluster_size + .. option:: extended_l2 - Changes the qcow2 cluster size (must be between 512 and 2M). Smaller cluster - sizes can improve the image file size whereas larger cluster sizes generally - provide better performance. - - .. option:: preallocation - - Preallocation mode (allowed values: ``off``, ``metadata``, ``falloc``, - ``full``). An image with preallocated metadata is initially larger but can - improve performance when the image needs to grow. ``falloc`` and ``full`` - preallocations are like the same options of ``raw`` format, but sets up - metadata also. + Enables the Extended L2 Entries feature that divides each cluster into 32 + separately allocated sub-clusters. A larger cluster size can be used, thus + reducing metadata overhead, while still allowing fine-grained allocation. .. option:: lazy_refcounts @@ -196,6 +198,53 @@ options that are supported for it. filename`` to check if the NOCOW flag is set or not (Capital 'C' is NOCOW flag). + .. option:: preallocation + + Preallocation mode (allowed values: ``off``, ``metadata``, ``falloc``, + ``full``). An image with preallocated metadata is initially larger but can + improve performance when the image needs to grow. ``falloc`` and ``full`` + preallocations are like the same options of ``raw`` format, but sets up + metadata also. + + Supported runtime options: + + .. program:: qcow2 + .. option:: cache-clean-interval + + Clean unused cache entries after this time (in seconds). + + .. option:: cache-size + + Maximum combined metadata (L2 tables and refcount blocks) cache size. + + .. option:: encrypt.key-secret + + ID of secret providing qcow2 AES key or LUKS passphrase. + + .. option:: l2-cache-size + + Maximum L2 table cache size. + + .. option:: l2-cache-entry-size + + Size of each entry in the L2 cache. + + .. option:: pass-discard-request + + Pass guest discard requests to the layer below (on/off). + + .. option:: pass-discard-snapshot + + Generate discard requests when snapshot related space is freed (on/off). + + .. option:: pass-discard-other + + Generate discard requests when other clusters are freed (on/off). + + .. option:: refcount-cache-size + + Maximum refcount block cache size. + .. program:: image-formats .. option:: qed -- 2.39.1
