Updates to Dynamic Memory UI in SP1 RC - Part 1

Updates to Dynamic Memory UI in SP1 RC - Part 1

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In the release candidate build of service pack 1 for Windows Server 2008 R2 we have updated some parts of the Dynamic Memory user interface.

There were some top-level goals that we had with the Dynamic Memory user interface in the Hyper-V Manager (our MMC interface).  Specifically we wanted users to be able to:

  • Quickly see if their Hyper-V server was “in a good state”
  • Quickly identify if specific virtual machines did not have enough memory
  • Know how much memory was being used by each virtual machine
  • Know how far away from “good” a given virtual machine was

To do this we used the current memory column and the memory availability column.  Unfortunately, many users were confused by the memory availability column – specifically people were confused by what it meant to have a negative memory availability value.  Rather than relying on the hope that every Hyper-V user in the world would read my blog – we decided to change what we displayed:


Specifically we have removed the memory availability column and replaced it with the memory demand and memory status columns (as well as renaming “current memory” to “Assigned Memory”).  To understand what each of these columns display:

  • Assigned Memory
  • Like current memory in the beta release this simply displays how much memory is currently available to the virtual machine.
  • Memory Demand
  • This is a new value.  This displays the amount of memory needed by the virtual machine at the moment – not including the requested memory buffer.  So you can think of this as the minimum memory needed by the virtual machine.  If you see the assigned memory go below the memory demand then the virtual machine is likely to be paging (this is equivalent to a negative memory availability).
  • Memory Status
  • This is a simple column that shows “OK”, “Low” or “Warning”.  “OK” means that the virtual machine has at least 80% of its memory buffer.  “Low” means that the virtual machine has more than the memory demand, but less than 80% of the memory buffer.  “Warning” means that the virtual machine has less than the memory demand.


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  • When reading this blog, It gives me a feeling that only a small team is working on improving HyperV? Is that true or am I getting a wrong impression here?

    Because this blog is so down to earth that when compared with VMware seriousness, it feels like HyperV is not taken seriously by Microsoft. Especially when I read this: "Rather than relying on the hope that every Hyper-V user in the world would read my blog – we decided to change what we displayed"

    Anyway, rant mode off, I really enjoy this blog, I just wished it was more official and that a whole team would post on it, not one guy that from my point of view, seems like the HyperV ICON...

  • HI Ben.

    There is something that I think you are still missing in the Dynamic Memory design.

    A separation between "startup ram" and "minimum ram".

    i.e. - the option to configure startup ram of 8gb for a server,

    but if memory pressure begins, allow hyper-v to balloon some ram away if needed,

    down to the minimum configured by the admin, for example 4gb.

    This is for sql/exchange servers when we (sysadmins) know how much ram we want for that system,

    and better start with the optimal ram then wait for it to grow.

    But still allow it to play with dynamic memory if there is memory pressure (like cluster node failure).

    Yizhar Hurwitz


  • Kilimats -

    Never fear, there is quite a large team of people working on Hyper-V.  In fact - I often tell people that it is hard to say just how many people "work on Hyper-V" these days - as there are a number of teams at Microsoft that do not work directly on Hyper-V, but do a lot of work for Hyper-V (e.g. clustering, networking, etc...).

    I will take your feedback as a compliment - that I am able to be "down to earth" despite being part of the Microsoft corporate machine :-)

    Yizhar Hurwitz -

    You will want to read this post: blogs.msdn.com/.../scripting-dynamic-memory-part-5-changing-minimum-memory.aspx



  • Sorry, it wasn't obvious but it was a compliment yes :-)

    thanks for doing this blog, very valuable information

  • @ kilimats, this is Ben's personal blog

    The team blog for virtualization is separate and here: blogs.technet.com/.../virtualization

  • Thank's for that Ben, cleared it up for me! (PS, any way I can get totals of all the columns to display?)


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