VMware vSphere

 View Only
  • 1.  Vendor insists on 32 CPU and 128GB RAM VM for SQL...

    Posted Nov 10, 2012 01:13 AM

    They really want physical, but we have a virtual mandate and are fighting them.  Our blades are 2xE5 2670 8 core, 384 GBRAM, so we'll have 32 cores to ESX.  Is this going to run well if we give them their own server?  I'm not convinced....

    Thanks!



  • 2.  RE: Vendor insists on 32 CPU and 128GB RAM VM for SQL...

    Posted Nov 10, 2012 06:11 PM

    Since your physical host has 32 vCPU, I wouldn't put any VM on there bigger than 16-20 vCPU even if its alone. If you put a 32 vCPU VM on such a host you will run into performance issues with cpu scheduling. Each process in the host will fight for CPU time, not only the vCPU processes connected to your VM. You need some overhead in the cores department if you add CPU heavy VM. If you go ahead and do it track your CPU %Ready values in esxtop or vcenter. You don't want it above 5%. A VM with 16 vCPU can perform faster than and a 32 vCPU on such a host due to less time scheduling issues.

    Depending on the requirements you could give them a single blade. But then you loose availiblity compared to a VMware HA farm with vmotion options etc. The business would have to decide which requirements are more important. Performance vs ease of management and high availiblity.

    If the business requires both performance and availiblity they can always cash up to build a physical windows cluster. This means higher initial investment cost, more complex to manage (=more senior staff to admin cluster than single SQL server), one more complex piece in the existing IT landscape (time spent on this cluster when it comes to updates, patching etc could have been spent elsewhere by IT staff).

    Show the business the big picture consequences and let them decide. If they go with vendor recommendation it most likely require an extra investment in terms of cost. Either physical servers dedicated for SQL or buy one new ESXi host that have more physical CPU cores than 32.



  • 3.  RE: Vendor insists on 32 CPU and 128GB RAM VM for SQL...

    Posted Nov 11, 2012 12:01 AM

    As you are probably aware already, to be precise you have only 16  with 32 threads, so you vendor still has room for complaints unless you buckle up for some 4-socket system.

    Sounds like this is just another case of a vendor pulling out ridiculous hardware requirements from nowhere. Just because it contains the magic acronym "SQL" doesn't necessarily mean it will be a monstrous heavy-hitter per se. Not every database and application requires huge resources like this. Unless they can give you some solid numbers on how they arrived at this "best practice" and why it applies to your particular case, I would always doubt such requirements.

    One of the beauties of virtualization is that you can have a good, unbiased look from the outside of how a system utilizes it's available resources. If it really needs more vCPUs or memory, you can easily add more (hot-add even).

    The problem if you don't comply with their demand is that they might end up pointing fingers at this for every future issue with the application.

    For the option of running this single VM with 32 vCPUs on a dedicated host, I doubt it will interfere with the "host operations" and overhead all that much unless the VM *really* consumes all the CPU cycles provided by those 32 vCPUs. Besides host processes, of which there aren't really any significant ones (except for software iSCSI and occasional vMotions) take priority over VM processes.



  • 4.  RE: Vendor insists on 32 CPU and 128GB RAM VM for SQL...

    Posted Nov 11, 2012 08:08 AM

    BigDaddy1 wrote:

    They really want physical, but we have a virtual mandate and are fighting them.  Our blades are 2xE5 2670 8 core, 384 GBRAM, so we'll have 32 cores to ESX.  Is this going to run well if we give them their own server?  I'm not convinced....

    Thanks!

    one thing when working with vendors is that while your setup should be fine virtually when you have a problem you dont want them pointing the finger at your going virtual even though it has nothing to do with the issue. For something like this software which you didnt mention, Ill assume that the software is some thing larger which will cost 250k with install and consultants etc, so 10k-15k on a pshycal server is just a small aspect.

    it comes down to this, if they dont support it really, you dont want to hear that when there is a software bug on their side.... it happens.