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Dell PowerEdgeT20 - VM performance issues

Discussion in 'Servers and Enterprise Solutions' started by tom01, Mar 23, 2020.

  1. tom01

    Associate

    Joined: May 1, 2012

    Posts: 62

    Hi Guys,

    I'm having some problems with performance in some VMs on my T20. I've checked the CPU/Memory utilisation within ESXI and it looks absolutely fine.

    The problem is I have especially on one Windows 10 (Fresh install) VM is that they are running very very slow, MSTSC sessions dropping, extreme lag etc. When I've checked the task manager on the affected VM CPU and Ram utilisation looks healthy, lots of head room with around only 27% Ram usage and 30% CPU.

    I've allocated 2 CPU's to more intensive VM's, 1 CPU to the normal ones and all have a decent allocation of RAM.

    Sometimes when I remote in to the box it runs absolutely fine but then other times it is completely unusable. I have 4 VM's running in total at the moment.

    ESXI reports the following stats in monitor:
    CPU:
    Used: 4.5 GHz Free: 8.3 GHz

    Memory:
    Used: 22.66 GB Free: 9.25 GB

    Spec:
    4 CPUs x Intel(R) Xeon(R) CPU E3-1225 v3 @ 3.20GHz
    32GB Ram

    Sometimes when I remote in to a VM it runs very very slow for a while and then will become blistering quick, almost like there is some sort of lag whilst the hyper-visor re-allocates resource to the active VM. However I don't understand 1) Why this takes so long to get decent performance restored, 2) Why performance is so bad when there appears to be lots of computational resource available in the first place?

    Has anyone else experienced this? Or can shed any light on what is happening?
     
    Last edited: Mar 23, 2020
  2. Throrik

    Wise Guy

    Joined: Sep 15, 2009

    Posts: 1,328

    Location: Manchester

    Are you seeing any spikes in ESXTOP? CPU Ready/Wait status etc?

    Do the VMs have the latest VMware Tools?
     
  3. #Chri5#

    Soldato

    Joined: Feb 27, 2003

    Posts: 6,812

    Location: Shropshire

    What do the performance metrics for the storage look like?
     
  4. Avalon

    Soldato

    Joined: Dec 29, 2002

    Posts: 5,402

    Check the storage IO load, CPU/RAM usage isn't the only relevant metric.
     
  5. tom01

    Associate

    Joined: May 1, 2012

    Posts: 62

    Thanks for the reply, anything I should be looking out for in particular? I'm ok with CPU/Mem metrics but not IO loads.

    Edit: Here are some stats (MB/s).

    HDD spec:
    1TB 7200rpm 32MB Cache - 6Gb/s

    HDD with all my datastores on:
    * Read Rate: Average: 0.19 // Max: 9.52 // Min: 0
    * Write Rate: Average: 1.13 // Max: 11.21 // Min: 0.15

    Total Disk usage stats for the specific VM: Average: 0.54 // Max: 9.73 // Min 0
     
    Last edited: Mar 24, 2020
  6. #Chri5#

    Soldato

    Joined: Feb 27, 2003

    Posts: 6,812

    Location: Shropshire

    How many VMs have you got? Are they are all running from a single 1TB disk?
     
  7. tom01

    Associate

    Joined: May 1, 2012

    Posts: 62

    I have 4 VM's at present, all datastores are on a single 1TB disk.
     
  8. #Chri5#

    Soldato

    Joined: Feb 27, 2003

    Posts: 6,812

    Location: Shropshire

    What about the latency for the disk in ESXi?
     
  9. tom01

    Associate

    Joined: May 1, 2012

    Posts: 62

    ESXI is installed on the same disk as the VM's.
     
  10. #Chri5#

    Soldato

    Joined: Feb 27, 2003

    Posts: 6,812

    Location: Shropshire

    Sorry, I meant the disk latency in ESXi (should be where you found read/write rates). I wonder if the single disk is getting overwhelmed, so when the the VM goes slow, look at the latency. IIRC, you're limited to the last hour of metrics though.
     
  11. no idea what

    Sgarrista

    Joined: Oct 5, 2009

    Posts: 9,092

    Location: Lincolnshire

    That's your problem there right away. You need some solid state storage.
     
  12. TheRealDax

    Associate

    Joined: Saturday

    Posts: 2

    Like "no idea what" said.
    Use one Solid State for ESXi (or two for mirror), One Solid State for VM Operating Systems and applications, use the 1TB for your data (or also two in mirror if you want to be save not losing anything).