Re: Instability with NetBSD Dom0

[tg%gmplib.org@localhost (Torbjörn Granlund)]

  > (1) Would you agree that using plain files for DomUs tend to lead to
  >     stability issues?
  
  No, I exclusively use file-backed virtual disks for my domUs,
  and never seen this kind of issue.
  
  now I never used qemu-img-xen to create a disk image, but
  dd if=/dev/zero.  Is qemu-img-xen creating a sparse file ? this may
  be an issue.
  
Indeed qemu-img-xen created sparse files.

I got the system rebooted.  The console had a handful of messages about
mbuf allocation failure.

The sparse file that (apparently) triggered the problem was large, 20
GiB.  The Dom0 memory assignment is just 1 GiB.  There might be a
relation there; expanding a sparse file needs intermediate RAM.

I restarted the install of the 20 GiB DomU with a non-spare file.  No
problems this time.  I am expanding all other sparse files too; I'll
need to purchase a larger SSD, I'm afraid.  :-)

I think it would be user friendly to have vnd mounts of sparse file be
rejected.

-- 
Torbjörn
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