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High storage latency on ESXi host
  • GID VMNAME NVDISK CMDS/s READS/s WRITES/s MBREAD/s MBWRTN/s LAT/rd LAT/wr

    12953 dns - 1 0.00 0.00 0.00 0.00 0.00 0.000 0.000

    16904 fw - 2 5.84 0.00 5.84 0.00 0.02 0.000 18.408

    20481 vcsa - 13 16.58 0.00 16.58 0.00 0.08 0.000 37.582

    130847 - 2 0.00 0.00 0.00 0.00 0.00 0.000 0.000

    626694 deb - 2 12.06 0.00 12.06 0.00 0.46 0.000 6.586

    as you can see the is no much IOPS per VM, like vcsa VM latency I captured is floating between 20 and 100ms, while deb has similar IOPS but lower latency

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    High storage latency on ESXi host
  • That is the thing, my total IOPS are less than 150, with 4 disks in RAID 10 I believe I should get 300IOPS due to mirroring. If you look at the graph, red line is transfer in kbps and blue latency, why is it dropping when disk is highly utilised? I will post htop when I’m back from work.

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  • I've been going back and forth with this issue for some time but honestly I have no idea if the vCenter telemetry is something to rely on. I'm experiencing rather high latency on the storage on my VMs, most of them idle, only vCenter and virtual firewall generate some IOPS, 5 are shut down, other 3 VMs are linux machines that idle for 99%, even though they can spike 100ms per IO. Today I have decided to migrate a VM storage to another server to find that higher disk utilization reduces the latency on the host, how that makes any sense? I'm using P420 in RAID 10 with 4x4TB 7k SAS HDDs.

    Host latency:

    https://preview.redd.it/cqvmy550ty1c1.png?width=986&format=png&auto=webp&s=f5823391eb6cd82cb9612b44aa2768087bf619e1

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    As per the subject, can anyone recommend something affordable? I found 24 port Catalyst 3650 but they go not cheaper than £200.

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    Latency (+Internet Quality) Measuring
  • I’m not sure if Ubiquity provides this level of telemetry, is there a reason why would you need to run it few time a day? In any case, you can always run WinMTR from your host.

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    Slow speeds to servers on WAN
  • Are your firewalls virtual/ hardware? What traffic goes where, what is site b, where is it? Where is proxy? Draw a diagram.

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