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Will SAN ISCSI Bandwidth will be enough

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  • Will SAN ISCSI Bandwidth will be enough

    I have a network that contain the following server

    Microsoft Exchange 2010 "150 GB Database for about 70 user" "LCR Enabled"
    2 DC
    File Server "500 GB of Data"
    Oracle Database for our customized APP
    2 ISA Server
    Camera (20 IP Camera)
    VMWARE ESXi that is hosting about 20 VM
    Backup Software for all the servers

    Now I am moving to new server and planning to get an ISCSI Device DELL MD3200I Single Controller 4x 1 Gbps LAN and place all the data on it so there will be no more data on the local servers,
    but I wonder if a 4 Gbps can is enable to run all these services without having a bottleneck on the SAN Side

    Hope that anyone can offer me help for this


  • #2
    Re: Will SAN ISCSI Bandwidth will be enough

    It all depends...

    First you need to get some storage stats by collecting some disk performance counters from your servers (physical and virtual). For that, you may want to use Microsoft Assessment and Planning Toolkit. Note that VMware has a paid service called VMware Capacity Planner if you don't want to bother doing this capacity planning yourself.

    Then with the report you can figure out if 4 Gb is enough and design your storage network accordingly.

    BTW be aware that at any given time your maximum throughput for a TCP session to your storage will be of 1 gigabit maximum and not 4 gigabit has you might think.
    If you need more than 1 gigabit of throughput per TCP session, you might consider 10 GbE
    Last edited by PiroNet; 6th May 2012, 20:03.

    Freelance, Business Owner, Virtualisation & Cloud Computing Fan Boy, VCP4/5/Cloud, VCAP4/5-DCA/DCD, vEXPERT '10-'14, EMCCA-Specialist, VMware Alumni.


    • #3
      Re: Will SAN ISCSI Bandwidth will be enough

      A lot of times the bandwidth is not the limiting factor but the amount of iops the san can handle.
      I do not know if the Dell san can do mpio, but using mpio you can use multiple connections. Using 4 connections you can get 4 gigabit performance.
      But as PiroNet said: first use the MAP toolkit to get the data.

      MCITP sa, ea & va, [email protected]


      • #4
        Re: Will SAN ISCSI Bandwidth will be enough

        Thanks alot and sorry for the delay
        I will download and then reply with the result
        THanks alot


        • #5
          Re: Will SAN ISCSI Bandwidth will be enough

          personally, i think you're going to struggle with that SAN.

          Personally I think you need a dual controller, which would give you 8gb bandwidth as it would add an additional 4 1gb ports. You can probably upgrade the SAN and add in a second controller. if you think you'll benefit.

          dell does do mpio - so make sure you make use of it and set up your vmware to do proper round robin mpio on all your luns.

          I think the amoutn of vms (particularly if they're high io production vms), and in particular the Exchange server with its large db, is going to be a big issue for you with such a low bandwidth setup.

          make sure you also set up jumbo frames for the iscsi to take advantage of the 9000 MTU iscsi frames. make sure that you separate iscsi traffic from tcp-ip traffic either using vlans or separate switching infrastructure. Otherwise your iscsi frames will steamroll your tcpip traffic and your network will fall over or ebcome very flaky.

          gerth is right in that most of the time IOPS are a big factor. use IOmeter to try and work out the iops that all your systems need and then do some calculations to determine the amnount of IOPS your raid configurations are allowing. Different raid levels and the number of disks you put in them allow for differing levels of IOPS. you might find you need to change the raid setup to increase the iops and then place high IO vm;s etc onto luns on those arrays. changing raid levels may also mean that you lose usable space, so you have to balance what you need - iops vs space. luckily though you should be able to add up to about 192 disks onto that model SAN so you can always scale out a bit.

          also when taking into account raid levels and iops, bear in mind that you should be able to add shelfs of differing hard drives to your SAN. i.e you might have one shelf of 24 600gb 2.5inch 10000rpm SAS drives and another shelf of 3.5 7200RPM 2TB near-line SAS. By doing this you can have large luns of slower storage for less highly used data or low IO things, and on higher cost high speed disks you can create hi IO raid setups with luns for your high io vm's/databases/transaction logs/etc