Virtualization Pro

Jan 21 2009   7:04PM GMT

Getting started with iSCSI and VMware ESX

Rick Vanover Rick Vanover Profile: Rick Vanover

Many VMware ESX administrators are quite comfortable with fibre channel storage but have not ventured into the iSCSI world. I recently set up my first iSCSI configuration for a small VMware Infrastructure 3 installation and it was quite successful. Here are some takeaways:

iSCSI is quite easy to configure. ESX’s iSCSI support is fully available in the form of a software initiator that uses a VMkernel interface. “That easy?” you ask? Yes, it is really that easy.

Using Ethernet is convenient. Until this point, I have exclusively used fibre channel storage for virtual machine file system (VMFS) volumes. With the ESX iSCSI software initiator, I simply dedicated some gigabit network interface cards to the VMkernel interface and was ready to configure the iSCSI adapter. There is experimental support for a hardware initiator with the QLogic 4010 interface.

There is a minimal configuration for the storage adapter. ESX has an iSCSI software adapter listed in the storage adapters section of the VMware Infrastructure Client. Once you configure this interface, the system is ready to receive a LUN. The figure below shows the configuration of the software iSCSI interface:

iSCSI Storage configuration in the VI Client

After those pointers, I was quickly running with a LUN provided from the storage system. Once the LUN is presented to the host, it is indistinguishable from other VMFS volumes. Full VMotion, Distributed Resource Scheduler and other VMware tools are available on these volumes, including the esxcfg- series of commands.

If you are getting started with iSCSI, be sure to go through the drills related to configuration steps on ESX. Also, visit your system architecture plan and make sure that the iSCSI interfaces are provisioned well by not also holding other traffic, and be sure to check out VMware’s iSCSI configuration document available for download from the VMware website.

4  Comments on this Post

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  • Duhaas
    Rick, just curious to know how you have two scsi targets pointing @ the same lun? Do you have multiple ips pointing @ the same target?
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  • Rick Vanover
    There are multiple IPs on the storage device as separate targets, and then paths inward to the same LUNs.
    20 pointsBadges:
  • 1fizgig
    Rick, we implemented our VI3.5 infrastructure around the middle of last year entirely on iSCSI with an EMC SAN going to 2 HP C7000 blade chassis with 2 hosts in each chassis. This has worked 100% with no issue, and was chosen because even VMWare believed we could happily run over iSCSI in our environment. Capacity planner determined we could virtualize around 50 of our 55 servers, and we've slowly been migrating over the past months to great success. I'd thoroughly recommend going iSCSI as a starting point for a VI infrastructure - you could always migrate to FC if your infrastructure required.
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  • Duhaas
    1fizgig, just curious to know how many ip's you have defined on your EMC for the target. right now we have use three of the four ports of the datamover and lacp them back to a cisco switch, and just have one ip bound right now. do folks see performance increases with multiple ips pointing to same target?
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