Hyper-V Forgets VM's

i released july updates onto our network past weekend.  i'd deployed our new av previous week.  let's av mixed hyper-v , followed reboot made nice mess.   logged hyper-v lab on monday morning find half of vm's missing.  they're sitting fine (but idle) on storage.  it's hyper-v has "forgotten" ever existed.

i trawled through windows event logs (application , service logs - microsoft - windows - hyper-v-config - admin) , found series of these:

source: hyper-v-config

event id: 4096

level: error

the virtual machines configuration <big long guid> @ <path vm> no longer accessible: requested operation cannot performed on file user-mapped section open. (0x800704c8)

ok.  bit of googling found entry on technet forums says need disable scanning vhd's , xml files of vm's.  ouch! doublechecked av , found hadn't done thought had.

ok, did , rebooted hyper-v lab server.  still no dice.  actually, hyper-v doesn't bother attempting load these vm's now.  far it's concerned, never existed.  ok, i'll in other virtualisation product; i'll open them.  ick ... no open command.  import?  not option because appears:

a) export/import layouts different of running vm.
b) i'll lose snapshots.  bad because i'll lose lots of work.

so i've got plethora of vm's sitting on disk snapshots cannot load up.  way forward re-add virtual hard disks new vm's.  pain:

• i lose my snapshots.
• i have reconfigure every single vm missing.
• each vm has pnp dance "new" nic , have reconfigure ipv4 addressing.
• it's lots of work shouldn't have do.

my questions are:

1) how can reload vm's without losing work?  i'd expect possible in enterprise product.
2) can done prevent hyper-v forgetting vm's?  can accept hyper-v refusing to load vm's files being accessed else.  admin can fix else can start vm.  however, having vm being removed hyper-v i'd expect dodgy piece of shareware.  , chance lose of vm's on 16 node cluster because junior operator screws av config (or else) not @ all!

i've been big fan of hyper-v big issue.

thanks,

aidan f.

btw, rtm release.

hi aidan:

"av irrelevant here"
not true - have known issue forefront can cause problem you're seeing. http://support.microsoft.com/kb/952265

"what concern (and people ignoring knows why!) hyper-v forgetting vm's if can't load files."
not true - addressed behavior question active scanning antivirus.

what work doing requires snapshots used? image building guess?

"admins have mad panic customers scream on losing vm's can't recover."
what mean? saying vhds gone? or configuration information? are vms completely removed displaying in center panel ui?

what happens if uninstall av software on lab setup , attempt repro behavior? hyper-v still "forget" configured vms after reboot?

if believe have issue hyper-v , none of suggestions we're discussing apply, open case , send me case number. sdwyer@microsoft.com

Windows Server  >  Hyper-V