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  • 1.  Disk performance significantly reduced after snapshot

    Posted May 21, 2021 04:05 PM

    This is a strange behavior and I'm trying to find out if anyone has any light to shed on this. The environment is 6.0 with latest update and its a dell server with pci mounted 2TB sing nvme chip. We have a ubuntu 18 or 20 installed as a vm (but that doesn't really matter). Running a disk test through fio we get disk performance of 400MB/s in rand read. However, when after snapshot is performed the performance drops to around 100MB/s. I'm not so much interested in the numbers itself as much as the the percentage drop. This was done in isolation and nothing else running on the host it self. I have replicated this every single time. When snapshot gets removed the performance goes back to 400 levels.

    My setup is that esxi is installed on spindle drives and the entire machine is on the nvme drive by itself. 


    Has anyone else experienced something like that ?

  • 2.  RE: Disk performance significantly reduced after snapshot

    Broadcom Employee
    Posted May 21, 2021 07:16 PM

    What’s your concern? Do you expect VMs to be left with snapshots for prolonged periods? Have you tried a newer version of ESXi since 6.0 is no longer updated or supported? If you stick with 6.0 have you looked for an updated driver for the disk controller?