3 Replies Latest reply on Aug 5, 2016 6:03 AM by maaboo

    Slow SAN Performance

    JimKnopf99 Master

      Hello together,


      we have an issue with our vm san throughput.

      Following tests that we have done so far.


      Build a SLES 11 SP3 VM with a RAW Device on NetApp Storage.

      CISCO Blade Server

      HP DL 380 G8 (latest driver versions) and higher vmware patch level 5.5, 2143827

      NetApp Metro Cluster with DataOntap 8.2.4 FP2

      ESXi Version 5.5 2068190

      Brocade SAN Environment


      When we write an 10 GB File on the RAW Volume with a 1 MB Block size, we get around 250 MB/s.


      When we do the same on a Hardware SLES 11 SP3 and do that test on the same LUN we get around 1,5 GB/s.

      The Hardware Server is using the same NetApp, same Brocade infrastructure and has only a 4 GB FC adapter.

      Cisco UCS is using a 8 GB FC Adapter.


      So the NetApp is performing well. Also the SAN infrastructure seems to be not the issue.



      We did the same test also on a HP ESXi environment with a 4 GB FC adapter. Same result. Slow.

      It doesn´t matter if we are using an paravirtualized or a LSI Logic Adapter at vmware level.


      All our ESXi Server are configured with the NetApp VSC Plugin so that we are using the recommended settings for NetApp and VMware.


      Any hints are appreciated


        • 1. Re: Slow SAN Performance
          Wscholz Enthusiast

          So if i get you right you a one volume wit a lun inside on the netapp. If you map the lun to the physical machine you get 1,5gb/s, if you map it to the esx and present it as a raw device to a vm you get 250mb/s.


          In what mode have you configured the raw device, physical or virtual mode ?

          Have you checked the hba´s on the esx regarding utilization, errors etc ?

          • 2. Re: Slow SAN Performance
            JimKnopf99 Master


            sorry for my delayed answer but we are still investigate that issue.

            Yes, you are right, Physical performance on same netapp is multiple times better than VM performance.

            We have checked both. pRDM and vRDM and also VMFS.


            • 3. Re: Slow SAN Performance
              maaboo Novice

              Any updates? I'm experiencing similar situation but we're using BL460c (in C7000)<->Brocade 8 Gb<->3PAR 7400.


              On bare metal W2K12 I've got 1500 MBps with Crystal DiskMark and about 450 MBps with file copy.


              On ESXi I've got about 130 MBps no matter inside VM or directly from HV.