gessi
Contributor
Contributor

When/why to use iSCSI Raw Devices via vSphere rather than directly from the VM?

Hello,

I am playing around with vSphere ESXi and wondering what advantage

I would have to use an iSCSI LUN as Raw Device connected via the VMWare

iSCSI initiator rather than installing an iSCSI initiator on my Windows

2003 R2 Virtual machine and connecting to the iSCSI Lun without VMWare?

What specific pro and contras are herefore?

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2 Replies
joshp
Enthusiast
Enthusiast

One benefit of using the ESX(i) initiator rather than an initiator inside a guest is that iSCSI traffic (storage I/O) processing is handled by the hypervisor (vmkernel) when using the ESX(i) software iSCSI initiator rather than placing the iSCSI processing load inside the guest. Additionally, with the use of hardware iSCSI initiators you can see even better performance when using the iSCSI outside the guest (eg. TCP/IP offload). Also, it just seems easier to present an iSCSI LUN to ESX(i) and format it as a VMFS datastore. You have more options with an iSCSI VMFS datastore than just connecting to an iSCSI LUN directly from a VM.

VCP 3, 4

www.vstable.com

VCP 3, 4 www.vstable.com
binoche
VMware Employee
VMware Employee

1 reason is ESX has native multipathing to most of iSCSI arrays, I am not sure if Windows 2003 has or not

binoche, VMware VCP, Cisco CCNA

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