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Re: VMs on external storage CPU overloading

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That's the problem: An internal SSD is connected relatively directly to the
CPU. Almost all USB keys aren't optimised for fast data transfer other
than, perhaps, reading/buffering large  single files. Running a VM means
constant read/write, constant update - it would be all the same as pushing
a CPU to constant use of a swap file/swap partition. It's massively
stressful on I/O - if you've a USB 2.x device, it transfers (very) slowly
compared to USB 3.x.

[For an illustration: even identical USB sticks will also vary: writing
2.7GB DVD images to a set of USB 2.0 sticks a couple of weeks ago: most of
them took six minutes, one took 35 - poor i/o and constantly swapping to
check (I used dd with the oflag=sync option - essential for data
integrity.) ]

The nearest comparison would be using a nice new NVME device. Inside a
laptop, in an M.2 slot - as fast as you like. Put it into an external USB
connected caddy - via USB 3.1 - for data transfer to another NVME inside
the laptop and it will be slightly to significantly slower. Same chip, same
laptop, moderated through a slower connection. That's the difference
between your VM on internal disk and your VM on USB stick

On Sat, Aug 1, 2020 at 8:44 AM john doe <johndoe65534@mail.com> wrote:

> On 7/31/2020 2:52 PM, Stefan Monnier wrote:
> >> IMO, allthose question as irrelevant - the problem is the IO. You can
> try it
> >> easily. get USB 2.0 and put a VM on it -
> >
> > I have and have had no such problems.
> > I strongly suspect that there's something else at play.
> > E.g. its VM is performing a lot of disk IO.
> >
>
> Can you expand on your thoughts?
>
> The issue only arises when the usbkey is used.
>
> --
> John Doe
>
>

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VMs on external storage CPU overloading john doe <johndoe65534@mail.com> - 2020-07-30 16:20 +0200
  Re: VMs on external storage CPU overloading john doe <johndoe65534@mail.com> - 2020-07-30 16:50 +0200
    Re: VMs on external storage CPU overloading Dan Ritter <dsr@randomstring.org> - 2020-07-30 17:30 +0200
      Re: VMs on external storage CPU overloading john doe <johndoe65534@mail.com> - 2020-07-30 17:50 +0200
      Re: VMs on external storage CPU overloading john doe <johndoe65534@mail.com> - 2020-08-03 22:30 +0200
        Re: VMs on external storage CPU overloading Michael Stone <mstone@debian.org> - 2020-08-03 23:10 +0200
          Re: VMs on external storage CPU overloading john doe <johndoe65534@mail.com> - 2020-08-04 08:50 +0200
        Re: VMs on external storage CPU overloading David Christensen <dpchrist@holgerdanske.com> - 2020-08-03 23:30 +0200
  Re: VMs on external storage CPU overloading Dan Ritter <dsr@randomstring.org> - 2020-07-30 16:50 +0200
  Re: VMs on external storage CPU overloading deloptes <deloptes@gmail.com> - 2020-07-30 22:10 +0200
  Re: VMs on external storage CPU overloading Stefan Monnier <monnier@iro.umontreal.ca> - 2020-07-30 23:00 +0200
    Re: VMs on external storage CPU overloading deloptes <deloptes@gmail.com> - 2020-07-31 08:00 +0200
      Re: VMs on external storage CPU overloading john doe <johndoe65534@mail.com> - 2020-07-31 10:40 +0200
        Re: VMs on external storage CPU overloading Andrei POPESCU <andreimpopescu@gmail.com> - 2020-08-02 09:40 +0200
      Re: VMs on external storage CPU overloading Stefan Monnier <monnier@iro.umontreal.ca> - 2020-07-31 15:00 +0200
        Re: VMs on external storage CPU overloading deloptes <deloptes@gmail.com> - 2020-08-01 01:30 +0200
          Re: VMs on external storage CPU overloading Stefan Monnier <monnier@iro.umontreal.ca> - 2020-08-03 06:00 +0200
        Re: VMs on external storage CPU overloading john doe <johndoe65534@mail.com> - 2020-08-01 10:50 +0200
          Re: VMs on external storage CPU overloading Andrew Cater <amacater@gmail.com> - 2020-08-01 11:50 +0200
            Re: VMs on external storage CPU overloading john doe <johndoe65534@mail.com> - 2020-08-01 12:10 +0200
          Re: VMs on external storage CPU overloading Stefan Monnier <monnier@iro.umontreal.ca> - 2020-08-03 06:00 +0200

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