<div dir="ltr"><br><div class="gmail_extra"><br><div class="gmail_quote">On Tue, Jul 11, 2017 at 2:59 PM, Gianluca Cecchi <span dir="ltr"><<a href="mailto:gianluca.cecchi@gmail.com" target="_blank">gianluca.cecchi@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr">Hello,<div>I have a source oVirt environment with storage domain on FC</div><div>I have a destination oVirt environment with storage domain on iSCSI</div><div>The two environments can communicate only via the network of their respective hypervisors.</div><div>The source environment, in particular, is almost isolated and I cannot attach an export domain to it or something similar.</div><div>So I'm going to plan a direct move through dd of the disks of some VMs</div><div><br></div><div>The workflow would be</div><div>On destination create a new VM with same config and same number of disks of the same size of corresponding source ones.</div><div>Also I think same allocation policy (thin provision vs preallocated)</div><div>Using lvs -o+lv_tags I can detect the names of my origin and destination LVs, corresponding to the disks</div><div>When a VM is powered down, the LV that maps the disk will be not open, so I have to force its activation (both on source and on destination)</div><div><br></div><div>lvchange --config 'global {use_lvmetad=0}' -ay vgname/lvname<br></div><div><br></div><div>copy source disk with dd through network (I use gzip to limit network usage basically...)</div><div>on src_host:</div><div>dd if=/dev/src_vg/src_lv bs=1024k | gzip | ssh dest_host "gunzip | dd bs=1024k of=/dev/dest_vg/dest_lv"<br></div><div><br></div><div>deactivate LVs on source and dest</div><div><br></div><div>lvchange --config 'global {use_lvmetad=0}' -an vgname/lvname<br></div><div><br></div><div>Try to power on the VM on destination</div><div><br></div><div>Some questions:</div><div>- about overall workflow</div><div>- about dd flags, in particular if source disks are thin vs preallocated</div><div><br></div><div>Thanks,</div><div>Gianluca</div><div><br></div></div>
</blockquote></div><br></div><div class="gmail_extra"><br></div><div class="gmail_extra">Some further comments:</div><div class="gmail_extra"><br></div><div class="gmail_extra">- probably better/safe to use SPM hosts for lvchange commands both on source and target, as this imply metadata manipulation, correct?</div><div class="gmail_extra">- when disks are preallocated, no problems, but when they are thin, I can be in this situation</div><div class="gmail_extra"><br></div><div class="gmail_extra">source disk defined as 90Gb disk and during time it has expanded up to 50Gb</div><div class="gmail_extra">dest disk at the beginning just after creation will normally be of few GB (eg 4Gb), so the dd command will fail when fulll...</div><div class="gmail_extra">Does this mean that it will be better to create dest disk as preallocated anyway or is it safe to run </div><div class="gmail_extra">lvextend -L+50G dest_vg/dest_lv</div><div class="gmail_extra">from command line?</div><div class="gmail_extra">Will oVirt recognize its actual size or what?</div><div class="gmail_extra"><br></div><div class="gmail_extra"><br></div></div>