<span style="color:rgb(34,34,34);font-family:arial,sans-serif;font-size:14px;background-color:rgb(255,255,255)">Does it make sense to shutdown instance before doing snaphotting, and then make a lvm snaphot of instance disk. This would be safe for instance though it‘s not some sort of 'live snaphot'.</span> <br>
<br><div class="gmail_quote">2012/7/16 Boris Filippov <span dir="ltr"><<a href="mailto:bfilippov@griddynamics.com" target="_blank">bfilippov@griddynamics.com</a>></span><br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
Current snapshot implementation for libvirt driver doesn't support snapshotting for everything except qcow2 (as i remember, because <span style="color:rgb(34,34,34);font-size:14px;font-family:arial,sans-serif">virDomainManagedSave will fail on everything except qcow2</span>). So, maybe we can discuss it here. This for sure can be implemented for lvm using lvm snapshots but it will be unsafe doing snapshot on alive instance. LVM is much like raw right now and raw doesn't support snapshots with current logic too. <br>
<br><br><div class="gmail_quote">2012/7/16 Li Wang <span dir="ltr"><<a href="mailto:foxban@gmail.com" target="_blank">foxban@gmail.com</a>></span><br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div><div class="h5">
<span style="color:rgb(34,34,34);font-size:14px;font-family:arial,sans-serif">hi, all</span><br style="color:rgb(34,34,34);font-size:14px;font-family:arial,sans-serif">
<br style="color:rgb(34,34,34);font-size:14px;font-family:arial,sans-serif"><span style="color:rgb(34,34,34);font-size:14px;font-family:arial,sans-serif"> As LVM backend image support was introduced in the trunk version of nova, is there any plan to support snapshot of the LVM backend image?</span><br style="color:rgb(34,34,34);font-size:14px;font-family:arial,sans-serif">
<br style="color:rgb(34,34,34);font-size:14px;font-family:arial,sans-serif"><span style="color:rgb(34,34,34);font-size:14px;font-family:arial,sans-serif"> I am using libvirt and Xen, with lvm as the instance image backend.</span><br style="color:rgb(34,34,34);font-size:14px;font-family:arial,sans-serif">
<br style="color:rgb(34,34,34);font-size:14px;font-family:arial,sans-serif"><span style="color:rgb(34,34,34);font-size:14px;font-family:arial,sans-serif"> There are two issues when creating snapshot.</span><br style="color:rgb(34,34,34);font-size:14px;font-family:arial,sans-serif">
<br style="color:rgb(34,34,34);font-size:14px;font-family:arial,sans-serif"><span style="color:rgb(34,34,34);font-size:14px;font-family:arial,sans-serif"> 1. when calling managedSave, libvirt complained there's no supported function by the driver.</span><br style="color:rgb(34,34,34);font-size:14px;font-family:arial,sans-serif">
<br style="color:rgb(34,34,34);font-size:14px;font-family:arial,sans-serif"><span style="color:rgb(34,34,34);font-size:14px;font-family:arial,sans-serif"> "libvirtError: this function is not supported by the connection driver: virDomainManagedSave"</span><br style="color:rgb(34,34,34);font-size:14px;font-family:arial,sans-serif">
<br style="color:rgb(34,34,34);font-size:14px;font-family:arial,sans-serif"><span style="color:rgb(34,34,34);font-size:14px;font-family:arial,sans-serif"> 2. when actually creating snapshot, libvirt calls qemu-img, which does not support lvm.</span><br style="color:rgb(34,34,34);font-size:14px;font-family:arial,sans-serif">
<br style="color:rgb(34,34,34);font-size:14px;font-family:arial,sans-serif"><span style="color:rgb(34,34,34);font-size:14px;font-family:arial,sans-serif"> As a result, snapshot status is always 'queue', and actually it's failed.</span><br style="color:rgb(34,34,34);font-size:14px;font-family:arial,sans-serif">
<br style="color:rgb(34,34,34);font-size:14px;font-family:arial,sans-serif"><br style="color:rgb(34,34,34);font-size:14px;font-family:arial,sans-serif"><span style="color:rgb(34,34,34);font-size:14px;font-family:arial,sans-serif"> For issue 1, it seems that libvirt does not support "save" or similar functions for xen, some modifications to the libvirt Xen driver maybe help?</span><br style="color:rgb(34,34,34);font-size:14px;font-family:arial,sans-serif">
<br style="color:rgb(34,34,34);font-size:14px;font-family:arial,sans-serif"><span style="color:rgb(34,34,34);font-size:14px;font-family:arial,sans-serif"> For issue 2, I think the snapshot action should call lvm related command but not qemu-img when using lvm.</span><br style="color:rgb(34,34,34);font-size:14px;font-family:arial,sans-serif">
<br style="color:rgb(34,34,34);font-size:14px;font-family:arial,sans-serif"><span style="color:rgb(34,34,34);font-size:14px;font-family:arial,sans-serif"> For example: lvcreate --snapshot ..........</span><br style="color:rgb(34,34,34);font-size:14px;font-family:arial,sans-serif">
<br style="color:rgb(34,34,34);font-size:14px;font-family:arial,sans-serif"><br style="color:rgb(34,34,34);font-size:14px;font-family:arial,sans-serif"><span style="color:rgb(34,34,34);font-size:14px;font-family:arial,sans-serif"> Further discussions and replies are welcome.</span><br style="color:rgb(34,34,34);font-size:14px;font-family:arial,sans-serif">
<br style="color:rgb(34,34,34);font-size:14px;font-family:arial,sans-serif"><span style="color:rgb(34,34,34);font-size:14px;font-family:arial,sans-serif"> Thanks all</span><br style="color:rgb(34,34,34);font-size:14px;font-family:arial,sans-serif">
<br style="color:rgb(34,34,34);font-size:14px;font-family:arial,sans-serif"><br style="color:rgb(34,34,34);font-size:14px;font-family:arial,sans-serif"><span style="color:rgb(34,34,34);font-size:14px;font-family:arial,sans-serif">Regards</span><div style="color:rgb(34,34,34);font-size:14px;width:22px;font-family:arial,sans-serif;margin:2px 0px 0px;padding:10px 0px;outline:none">
<div style="background-color:rgb(241,241,241);border:1px solid rgb(221,221,221);clear:both;line-height:6px;outline:none;width:20px"><img style="background-image:url('');min-height:8px;width:20px;background-repeat:no-repeat no-repeat"></div>
<span><font color="#888888">
</font></span></div><span><font color="#888888"><div style="color:rgb(34,34,34);font-size:14px;font-family:arial,sans-serif"><br></div><span style="color:rgb(34,34,34);font-size:14px;font-family:arial,sans-serif"><font color="#888888"><br>
Wang Li</font></span>
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