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authorHu Tao <hutao@cn.fujitsu.com>2014-09-10 17:05:49 +0800
committerKevin Wolf <kwolf@redhat.com>2014-09-12 15:43:06 +0200
commit0e4271b711a8ea766d29824c844e268b91ac3ae5 (patch)
tree8d00320ff6821eca68094864906838f3f4f5a6fe /qemu-img.texi
parent06247428be8037b3739280f82cb29efe8397695f (diff)
qcow2: Add falloc and full preallocation option
preallocation=falloc allocates disk space by posix_fallocate(), preallocation=full allocates disk space by writing zeros to disk. Both modes imply preallocation=metadata. Signed-off-by: Hu Tao <hutao@cn.fujitsu.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Diffstat (limited to 'qemu-img.texi')
-rw-r--r--qemu-img.texi8
1 files changed, 5 insertions, 3 deletions
diff --git a/qemu-img.texi b/qemu-img.texi
index d64d05edda..50d2cca7a0 100644
--- a/qemu-img.texi
+++ b/qemu-img.texi
@@ -476,9 +476,11 @@ sizes can improve the image file size whereas larger cluster sizes generally
provide better performance.
@item preallocation
-Preallocation mode (allowed values: off, metadata). An image with preallocated
-metadata is initially larger but can improve performance when the image needs
-to grow.
+Preallocation mode (allowed values: @code{off}, @code{metadata}, @code{falloc},
+@code{full}). An image with preallocated metadata is initially larger but can
+improve performance when the image needs to grow. @code{falloc} and @code{full}
+preallocations are like the same options of @code{raw} format, but sets up
+metadata also.
@item lazy_refcounts
If this option is set to @code{on}, reference count updates are postponed with