Re: Poor harddrive performance on VM

[Paul Leiber <paul@xxxxxxxxxxxxxxxx>]

Am 02.11.2024 um 14:31 schrieb KAĞAN IŞILDAK:
> I wonder if xenserver's guesttool is compatible with vanilla xen?
I have no idea. I installed drivers via Windows Update.

> I tried to install development builds with different options about 5
> times but still boot hang occurs in all windows versions after xenbus
> installation.
Sorry to hear that. I am running out of ideas what to try. Perhaps some 
Xen DomU configuration that is causing problems?
> Paul Leiber <paul@xxxxxxxxxxxxxxxx>, 2 Kas 2024 Cmt, 12:54 tarihinde şunu yazdı:
> > Am 02.11.2024 um 10:43 schrieb KAĞAN IŞILDAK:
> > > I tried to install PV drivers on Win10 vm but after xenbus installation
> > > vm stuck on booting phase.
> > > Is PV drivers only solution to solve problem?
> > Yes, I think you need the PV drivers to increase HD speed.
> >
> > I faintly remember that the PV driver update process in Windows had some
> > issues from time to time (it's Windows, after all... :-). I always got
> > it working without major efforts, though. Unfortunately, I don't
> > remember the exact steps I took. Some ideas you could try, without
> > guarantee for success:
> > - Install the drivers again via Windows Update, reboot, try again if it
> > fails
> > - Manually install the drivers (via Windows Device Manager), reboot, try
> > again if it fails
> >
> > Paul
> >
> > > On Sat, Nov 2, 2024 at 12:40 Paul Leiber <paul@xxxxxxxxxxxxxxxx
> > > <mailto:paul@xxxxxxxxxxxxxxxx>> wrote:
> > >
> > >      Am 01.11.2024 um 11:17 schrieb KAĞAN IŞILDAK:
> > >       > Hello,
> > >       >
> > >       > I am using Xen 4.18. My host machine is a Dell server with dual
> > >      Intel®
> > >       > Xeon® Gold 6438Y+ CPUs and an NVMe SSD. I am working with Windows
> > >       > virtual machines and experiencing issues related to hard disk speeds.
> > >
> > >      Windows DomU means that it is a HVM type of VM.
> > >
> > >       > So far, I have conducted a total of four tests, covering disk format
> > >       > and BIOS firmware. I have tried both QCOW2 and RAW disk formats and
> > >       > booted the BIOS as both SeaBIOS and OVMF. In all four tests, my
> > >       > read/write speed was around 50 MB/s, which is really low.
> > >       >
> > >       > What could be causing this issue?
> > >       >
> > >       > Note: No PV driver is installed, and I have tried mounting the disks
> > >       > as both HDA and XVDA, but the results were the same.
> > >
> > >      IIUC, the PV on HVM drivers are necessary to gain the benefits of
> > >      paravirtualization. If there is no frontend PV driver counterpart in
> > >      the
> > >      DomU for the PV backend on the Dom0, then less efficient software
> > >      virtualization happens. [1]
> > >
> > >      I'd try to install the PV drivers. In my Windows VMs, the Xen PV
> > >      devices
> > >      have been detected and the Citrix drivers have been installed
> > >      automatically by Windows Update.
> > >
> > >      Paul
> > >
> > >      [1] https://wiki.xenproject.org/wiki/PV_on_HVM <https://
> > >      wiki.xenproject.org/wiki/PV_on_HVM>