Markus, Andrew, I'm neigher on iSCSI side nor NFS. I'm on Netapp side, and I understand it is not perfect.
Lets say iSCSI is more common on systems I installed.
But iSCSI is not so bad, especially on Netapp. Netapp technologies work for iSCSI.
>Some NFS provisioning benefits could be get by LUN provisioning and dedup in iSCSI world.
With NFS I get my space transparently and immediately back, the view from the storage is the same as from ESX, isn't it?
++++Agree. Storage view is not so transparent, but you get near the same result!
The worst thing with iSCSI is that LUN never decreases in size. That really bad. But does vmdk decreease if I delete some data from host OS?
>Easy restores from snapshots (NFS) vs lun cloning (iSCSI)
The point is, that I can enter the snapshot-directory directly and copy out the needed files, eg. to compare two different *.vmx. With iSCSI one must clone the LUN, map it, rescan on ESX to get the new store.... so NFS is much more admin-friendly.
++++Yes, but usually vmdk is pretty large itself (gigabytes). So that copyng takes plenty of time. LUN cloning can be done in seconds.
FlexClone license (or SnapRestore file restore maybe) solves the issue and you need just export the clone, but, again, it costs money.
>You store data in vmdk on NFS, so you'll need VMWare to get your data.
Uh? And in an iSCSI-LUN-Datastore you don't?
In fact there are more ways to get to the data that is inside a vmdk when it is stored on NFS: you could mount the volume from a third machine (I am not saying everyone should do that all the time -get me right), copy the needed files away from active file system or snapshot, then there are tools to mount and interpret vmdk-files, even with an NTFS in it.
In contrast to iSCSI here is at least one more step: you need a tool to interpret VMFS before you get your vmdk.
++++ I mean to keep data on NTFS LUNs, not VMFS, to be able mount it to any other Windows and get data running immediately.
Andrew, thank you for a good link.
But I think you still need SMVI to get VMs consistent. And SMVI just hangs with NFS. (as I mentioned it should be fixed in recent VMWare update)
Datastore size increase could be pain with iSCSI sometimes, i.e. when extent size is less than desired vmdk size. In other situations it works ok.
So the main disadvantage for is NFS is price.... NFS license is one of the most expensive and in Windows environemnts it will be used for VMware only.
It is not a problem in big bussineses and with large number of VMs I would go for NFS. With low end and mostly Windows hosts I'll go for iSCSI.