ESXi 6 Lun Extents

My organization has recently purchase a NetApp SAN and the max Lun size in VMware is 15TB. We have a request to preset a 20TB Lun to a VM. I know using extents is an option but feel very uneasy doing this since if something happens to one Lun, the whole volume goes offline. Am I being overly paranoid? How are other dealing with this issue?
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compdigit44Asked:
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Andrew Hancock (VMware vExpert / EE MVE^2)VMware and Virtualization ConsultantCommented:
My organization has recently purchase a NetApp SAN

Welcome to the 21st Century! - LOL!

max Lun size in VMware is 15TB
Why ? Is this what you created ? Max LUN Size is 64TB to an ESXi host.

I know using extents is an option but feel very uneasy doing this since if something happens to one Lun, the whole volume goes offline. Am I being overly paranoid?

Paranoia! But you have a right to question, we've had a number of Posts on EE, where a LUN has been deleted, removed, and the WHOLE datastore has then been corrupted!!!

How are other dealing with this issue?

Document it, so the VMware/Storage Team know which LUNs, e.g. LUN 1 + LUN2 = DATASTORE 4...

Are you expanding the existing LUN, or adding another LUN to create the datastore.
Paul SolovyovskySenior IT AdvisorCommented:
Which Netapp SAN are you using?   Are you using 7 mode or cDot?
compdigit44Author Commented:
We have 4 FAS2620 nodes. Also we are using Fiber cables. Our SAN Admin stated he confirmed through support that a max Lun size for NetApp in Vmware is 15TB

https://community.netapp.com/t5/Data-ONTAP-Discussions/VMware-max-LUN-size/td-p/142292


https://www.netapp.com/us/media/tr-4597.pdf
Active Protection takes the fight to cryptojacking

While there were several headline-grabbing ransomware attacks during in 2017, another big threat started appearing at the same time that didn’t get the same coverage – illicit cryptomining.

Andrew Hancock (VMware vExpert / EE MVE^2)VMware and Virtualization ConsultantCommented:
That's a NetApp limitation LUN Size Max 16TB (well OnTap to be correct), if you need larger datastore use Extents.

Just document!

or use NFS.
compdigit44Author Commented:
Any performance issues with using extents?
Andrew Hancock (VMware vExpert / EE MVE^2)VMware and Virtualization ConsultantCommented:
We would argue, using LUNs gives performance issues versus NFS, because NetApp OnTap is build on NFS, and additional layer for FC/iSCSI.

We've switched majority our our NetApp Filers from LUNs to NFS many years ago now.

Should not be any performance issues, just make sure you document well, and watch NetApp snapshots, and the LUN going offline!!!!!

Many LUNs making up a datastore, could cause chaos, if a LUN goes offline!

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