something along
echo - - - > /sys/class/scsi_host/hostX/scan // yes, the "-" must be there !
Unfortunately there is nothing under scsi:
[root@localhost ~]# ll /sys/class/scsi_* /sys/class/scsi_device: total 0
/sys/class/scsi_disk: total 0
/sys/class/scsi_host: total 0
I also tried kudzu (http://linux.die.net/man/8/kudzu), but it still shows only the original drive:
[root@localhost ~]# kudzu [root@localhost ~]# kudzu -p ... - class: HD bus: VIRTIO detached: 0 device: vda driver: virtio_blk desc: "Virtio Block Device" - ...
While looking around I found this comment (in a bug not directly related):
Yaniv Kaul 2009-05-19 06:53:14 EDT Hot-add is not supported for RHEV 2.1.
https://bugzilla.redhat.com/show_bug.cgi?id=501468#c1
So maybe it actually cannot work?