<html>
<head>
<meta http-equiv="content-type" content="text/html; charset=utf-8">
</head>
<body bgcolor="#FFFFFF" text="#000000">
<p>All,</p>
<p> Currently the "virsh save" command opens a file to save a
domain's XML and memory state, does the save, and then re-opens
the file to simulate seeking to the beginning to update the header
to indicate that the file is complete.</p>
<p>For pipes this is not possible, attempting to re-open the pipe
will not connect you to the same consumer. Seeking is also not
possible on a pipe.</p>
<p>Attached is a patch that detects if the file being written to is
not seekable, and if so writes the completed header initially,
then writes the normal data, and avoids re-opening the file.</p>
<p>This is useful to me for saving a VM state directly to Ceph RBD
images without having an intermediate file.<br>
</p>
<p>I've tested this patch successfully (against v1.3.5) for both
saving and restoring a domain:</p>
<p><tt># <b>( fifo="$(mktemp -u)"; mkfifo "${fifo}" &&
virsh save one-0 "${fifo}" & cat "${fifo}" | rbd import -
rbd/test1234 & wait; rm -f "${fifo}" )</b></tt><tt><br>
</tt><tt><br>
</tt><tt>Domain one-0 saved to /tmp/tmp.HK4hChiQqB</tt><tt><br>
</tt><tt><br>
</tt><tt># </tt><tt><br>
</tt></p>
<tt># <b>( fifo="$(mktemp -u)"; mkfifo "${fifo}" && rbd
export rbd/test1234 - > "${fifo}" & virsh restore
"${fifo}" & wait; rm -f "${fifo}" ) </b>
</tt><tt><br>
</tt><tt>Exporting image: 100% complete...done.</tt><tt><br>
</tt><tt>Domain restored from /tmp/tmp.0YaUZ5Y2yT</tt><tt><br>
</tt><tt><br>
</tt><tt># <b>virsh list</b></tt><tt><br>
</tt><tt> Id Name State</tt><tt><br>
</tt><tt>----------------------------------------------------</tt><tt><br>
</tt><tt> 11 one-0 running</tt><tt><br>
</tt><tt>#</tt><br>
<pre class="moz-signature" cols="72">--
Roy Keene
Knight Point Systems, LLC
Service-Disabled Veteran-Owned Business
1775 Wiehle Avenue Suite 101 | Reston, VA 20190
c: 813-956-3808 f: 571-266-3106
<a class="moz-txt-link-abbreviated" href="http://www.knightpoint.com">www.knightpoint.com</a>
DHS EAGLE II Prime Contractor: FC1 SDVOSB Track
GSA Schedule 70 SDVOSB: GS-35F-0646S
GSA MOBIS Schedule: GS-10F-0404Y
ISO 20000 / ISO 27001
Notice: This e-mail message, including any attachments, is for the
sole use of the intended recipient(s) and may contain confidential
and privileged information. Any unauthorized review, copy, use,
disclosure, or distribution is STRICTLY prohibited. If you are not
the intended recipient, please contact the sender by reply e-mail
and destroy all copies of the original message.</pre>
</body>
</html>