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mdparker
Contributor
Contributor

In vSphere5, should I use iSCSI at the Host or guest level

Hi all,

We are moving to vSphere5 with a 10GbE network and NFS datastores hosted by our NetApp 3240's.  For a few servers, we will need RDM luns via iSCSI as we'll not be using Fiber Channel.  Should I use the iSCSI initiator in the guest or iSCSI connect to the lun via the ESX host?

Thanks

Michael

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Texiwill
Leadership
Leadership

Hello,

If you use iSCSI via ESX then you have all the limits of Datastores within ESX.

If you use iSCSI initiators in the guests then that initiator code runs per guest and your networking could get a bit messy.

If it was me, I would present iSCSI to the Host over 10G so that data writes/reads are aggregated per Host and you get all the benefits of using VMFS or RDMs. This way the guest administrators (if not the virtualization administrators) also do not need to worry about the underlying storage.  But this also means you deal with the limits of using Datastores within ESX, but if you use RDMs most if not all those limits dissappear. But you can also take advantage of any multi-pathing and advanced network configurations for failover, etc.

You can also do that within the guest (well really the vSwitch) pointing to the Netapp as well, but this generally requires you to have multiple vNICs which does add to the complexity.

Best regards,
Edward L. Haletky
VMware Communities User Moderator, VMware vExpert 2009, 2010, 2011

Author of the books 'VMWare ESX and ESXi in the Enterprise: Planning Deployment Virtualization Servers', Copyright 2011 Pearson Education. 'VMware vSphere and Virtual Infrastructure Security: Securing the Virtual Environment', Copyright 2009 Pearson Education.
vSphere Upgrade Saga -- Virtualization Security Round Table Podcast

--
Edward L. Haletky
vExpert XIV: 2009-2023,
VMTN Community Moderator
vSphere Upgrade Saga: https://www.astroarch.com/blogs
GitHub Repo: https://github.com/Texiwill
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mdparker
Contributor
Contributor

Thanks for the reply. Makes total sense. Guess I'll be going the easier route through the host.

Sent from my iPhone

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AndreTheGiant
Immortal
Immortal

Another reason to use a guest iSCSI could be have the storage functions, like application consisten snapshots.

But remember that, if you have backup programs that works at vmdk level you will loose the guest iSCS disks from the backup sets.

Andrew | http://about.me/amauro | http://vinfrastructure.it/ | @Andrea_Mauro
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