doc: Fix doc for backingStore

I spent quite some time figuring that backingStore info
isn't included in the dom xml, unless guest is up and
running. Hopefully putting that in the doc should help.

Also, several people have complained that libvirt reports
a backing file as raw, even though they expected it to be
qcow2; where the culprit is usually the user forgetting to
create the file with qemu-img create -o backing_fmt=qcow2.

This patch adds that info to the doc.

Signed-off-by: Deepak C Shetty <deepakcs@redhat.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
This commit is contained in:
Deepak Shetty 2015-03-18 19:18:22 +05:30 committed by Eric Blake
parent e2660cb8a6
commit 060f4c666e

View File

@ -2108,14 +2108,22 @@
</dd>
<dt><code>backingStore</code></dt>
<dd>
This element describes the backing store used by the disk specified by
sibling <code>source</code> element. It is currently ignored on input
and only used for output to describe the detected backing chains.
<span class="since">Since 1.2.4</span>. An empty
<code>backingStore</code> element means the sibling source is
self-contained and is not based on any backing store. The following
attributes and sub-elements are supported in
<code>backingStore</code>:
This element describes the backing store used by the disk
specified by sibling <code>source</code> element. It is
currently ignored on input and only used for output to
describe the detected backing chains of running
domains <span class="since">since 1.2.4</span> (although a
future version of libvirt may start accepting chains on input,
or output information for offline domains). An
empty <code>backingStore</code> element means the sibling
source is self-contained and is not based on any backing
store. For backing chain information to be accurate, the
backing format must be correctly specified in the metadata of
each file of the chain (files created by libvirt satisfy this
property, but using existing external files for snapshot or
block copy operations requires the end user to pre-create the
file correctly). The following attributes and sub-elements are
supported in <code>backingStore</code>:
<dl>
<dt><code>type</code> attribute</dt>
<dd>