vCenter

 View Only

  • 1.  DRS keeps migrating same VMs

    Posted Nov 19, 2018 04:49 PM

    Hi, I have a cluster of about 20 hosts and 400 VMs.

    Vcenter 6.5 U2a, hosts 6.5

    DRS is fully automated with default threshold level.

    DRS keeps migrating same 5 VMs hundreds time per day.

    Is there a way to understand why is doing that and why is choosing always same VMs?

    Thanks in advance



  • 2.  RE: DRS keeps migrating same VMs

    Posted Nov 19, 2018 06:51 PM

    I've seen this in conjunction with DRS rules. For example, with a rule that pinned some VMs to a few hosts and these hosts were heavily loaded. Then it moves the VMs that are least used back and forth all the time.



  • 3.  RE: DRS keeps migrating same VMs

    Posted Nov 21, 2018 10:46 AM

    unfortunately this is not my case, all hosts are under 50% of utilization for both CPU and memory.

    I'm wondering if is there a way to view inside logs why those vms are choosen?



  • 4.  RE: DRS keeps migrating same VMs

    Posted Nov 21, 2018 11:21 AM

    How much RAM/CPU does those VMs have? Are those machines using memory/cpu intensive?



  • 5.  RE: DRS keeps migrating same VMs

    Posted Nov 21, 2018 12:04 PM

    are all small vms with 2/3 Gb of ram with cpu and ram in idle most of the time



  • 6.  RE: DRS keeps migrating same VMs

    Posted Mar 13, 2019 11:14 AM

    Hi,

         were you able to rectify it was showing such behavior?

    If you found answer please let me know.



  • 7.  RE: DRS keeps migrating same VMs

    Posted Mar 13, 2019 12:12 PM

    Hi

    Do you have any DRS affinity rules or anti affinity rules?



  • 8.  RE: DRS keeps migrating same VMs

    Posted Mar 13, 2019 02:23 PM

    yes we have both



  • 9.  RE: DRS keeps migrating same VMs

    Posted Mar 14, 2019 01:14 PM

    There's a fling for that!

    It is called DRS Dump Insight: VMware Labs - Flings

    it will help you figure out why VMs were migrated etc.



  • 10.  RE: DRS keeps migrating same VMs

    Posted Mar 13, 2019 02:23 PM

    not yet, currently we planned to upgrade vcenter to 6.5 2d cause in release notes we've found this:

    "vSphere DRS might run migrations of virtual machines even when a cluster seems balanced

    In vSphere 6.5, if vSphere DRS detects in a balanced cluster an imbalance between two hosts larger than a set migration threshold, it might run some migration operations that do not effectively improve the balance between the two hosts.

    This issue is resolved in this release"