[pve-devel] qemu-kvm online resize with device-backed storage

[Dmitry Petuhov]

Hello.

Looks like PVE's qemu is affected by bug 
https://bugzilla.redhat.com/show_bug.cgi?id=1070531

I think because of this resize is failing for CEPH with krbd enabled 
(seen several reports on forum). It also affects my custom DELL plugin.

After backing device is resized, I had error "qmp command 'block_resize' 
failed - Could not resize: Invalid argument".  Manual qmp command also 
failed:
     # block_resize drive-scsi1 16492674416640
     Could not resize: Invalid argument

Surprisingly,
     # block_resize drive-scsi1 15T

done job.

Just tested (in another machine) with megabytes instead of terabytes, 
also works OK:
     # block_resize drive-scsi0 8603566080
     Could not resize: Invalid argument

     # block_resize drive-scsi0 8205M

So maybe we could do something like
-    vm_mon_cmd($vmid, "block_resize", device => $deviceid, size => 
int($size));
+    vm_mon_cmd($vmid, "block_resize", device => $deviceid, size => 
ceil($size/1024/1024) . "M");
in PVE::QemuServer::qemu_block_resize() as workaround?