On 05/26/2017 07:40 AM, Kevin Wolf wrote: > Am 25.05.2017 um 20:44 hat Bruno Alvisio geschrieben: >> Hello John, >> >> Thanks. Yes, typo when I wrote the e-mail. >> >> It might be possible that XEN does that (I will ask in the XEN forum). >> However, >> I have noticed that it is not the case for all of the VMs I have launched. In >> some of them I can query the block devices even after a long time the VM has >> been running. >> >> I was wondering if the device is removed in case the disk is corrupted or >> something. When I mention it runs normally, I can log into ithe VM and >> perform >> read/write operations such creating files. >> >> Also, is there an easy way to log all qemu events so that I can see what >> might >> be going on with the 'ide' device? > > There is one completely crazy thing that Xen does with respect to disks. > Instead of having support for their PV disks (i.e. virtio-blk, just > different) in the BIOS, they add _both_ an IDE disk and a PV disk to the > VM, so that the bootloader or non-PV-aware guest OSes can access the IDE > disk, for which they most certainly do have drivers. As soon as a driver > for the PV disk is loaded, however, that driver calls a hypervisor > function that removes all the IDE disks from the VM and leaves only the > PV ones there, so that the PV-aware guest doesn't see two same disks. > > I suspect that what you're seeing initially is the IDE disks, and when > the PV driver is loaded, they disappear. > > Kevin >
Sure, but does that mean that you'd see *no* block devices via a query afterwards?
