iscsi vs nfs for esxi

[rostreich]

hello folks!

i read somewhere, that there is always a discussion of which method would be better for a datastore for an esxi server.

some say iscsi, others say nfs. i would like to hear some experience, specs and insights to enlighten me, as I have to setup one or more esxi servers in future.

i have experience with setting up esxi, but always on iscsi (more or less it's about multipath, which I love!). you'll get slightly routine, if you have done it a few times. i never touched nfs in any way.

also I heard, that a datastore is limited to 2TB on iscsi. is it true? at what point is it limited? whole sharing space? per partition?

and I would like to share with you the information, that the cheap-ass NIC RTL8169SC works ootb with the newest esxi!

[alexplatform]

Generally speaking, you use iSCSI when:
1. the storage has plenty of CPU available, as it is more CPU intensive then NFS (see http://www.vmware.com/files/pdf/storage ... l_perf.pdf)
2. When you need multipathing

you use NFS when:
1. Your storage is resource limited
2. When you have need to access the datastore from another host directly (you can share the store via other protocols simultaneously) A good example is your store of installer images or common software.
3. When the whole system is not mission critical.

also I heard, that a datastore is limited to 2TB on iscsi

true (esxi version <5.0) false (>5.0). It may not be a bad idea to check the system requirements of the software you wish to install-http://www.vmware.com/pdf/vsphere5/r50/ ... ximums.pdf

Getting around this limit even with older versions is trivial- just make multiple 2TB luns.

[rostreich]

ah this is good, I will stick then with iscsi.

Getting around this limit even with older versions is trivial- just make multiple 2TB luns.

thank you....I thought the limit came from iscsi itself....this is very good as I always use newest esxi!

[alexplatform]

thank you....I thought the limit came from iscsi itself.

Well, it sort of did. Before 4K addressing ALL SCSI devices were addressing limited to a maximum 2TB LUN limit (with some exceptions) which is the reason much software was hard coded for 512byte addressing regardless of hardware capability. Since the industry was slow to migrate to 4K and AF block arrangements, changes to initiator OSes was also slow. istgt (the iSCSI target used by N4F) has had large block capability for some time.