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Diffstat (limited to 'qemu-img.texi')
-rw-r--r-- | qemu-img.texi | 30 |
1 files changed, 29 insertions, 1 deletions
diff --git a/qemu-img.texi b/qemu-img.texi index 6fc3c28..77c6d0b 100644 --- a/qemu-img.texi +++ b/qemu-img.texi @@ -70,10 +70,15 @@ lists all snapshots in the given image Command description: @table @option -@item check [-f @var{fmt}] @var{filename} +@item check [-f @var{fmt}] [-r [leaks | all]] @var{filename} Perform a consistency check on the disk image @var{filename}. +If @code{-r} is specified, qemu-img tries to repair any inconsistencies found +during the check. @code{-r leaks} repairs only cluster leaks, whereas +@code{-r all} fixes all kinds of errors, with a higher risk of choosing the +wrong fix or hiding corruption that has already occured. + Only the formats @code{qcow2}, @code{qed} and @code{vdi} support consistency checks. @@ -232,6 +237,29 @@ to grow. @end table +@item qed +Image format with support for backing files and compact image files (when your +filesystem or transport medium does not support holes). Good performance due +to less metadata than the more featureful qcow2 format, especially with +cache=writethrough or cache=directsync. Consider using qcow2 which will soon +have a similar optimization and is most actively developed. + +Supported options: +@table @code +@item backing_file +File name of a base image (see @option{create} subcommand). +@item backing_fmt +Image file format of backing file (optional). Useful if the format cannot be +autodetected because it has no header, like some vhd/vpc files. +@item cluster_size +Changes the cluster size (must be power-of-2 between 4K and 64K). Smaller +cluster sizes can improve the image file size whereas larger cluster sizes +generally provide better performance. +@item table_size +Changes the number of clusters per L1/L2 table (must be power-of-2 between 1 +and 16). There is normally no need to change this value but this option can be +used for performance benchmarking. +@end table @item qcow Old QEMU image format. Left for compatibility. |