vSphere 4, NFS Vs iSCSI

[markroles]

Hi,

I'm about to be undertaking a new infrastructure and at this stage have the option of iSCSI or NFS target (same physical target)

I'm trying to determine which way to go and would like some ideas on the supported features / performamce.

I note that iSCSI s/w initiator has been vastly improved, does this make the performance better than using NFS (Host CPU, latency, speed).

Is ESX able to detect latencies, read/write MB/s etc when using NFS or is this still ilmited to block based storage?

Does the vStorage API feature 'Changed Block Tracking' work when your VMs are stored on NFS storage? If so, how? since surely it doesn't know which blocks have changed.

If all things are equal, then it's likely that I'll go with NFS as this offers other advantages, like ease of snapshot, clone and mounting.

Any other gotcha's I should look out fo, I've seen the latest NetApp going over the setup for IP based storage and that's all fine.

Thanks for any pointers

Mark

[timw18]

We are running nfs on netapp and it seems to be fine. I would have a look at the NetApp and VMware Virtual Infrastructure Storage Best Practices Technical Report for some tips on how you should configure your esx machines. ( Sorry don't have the link)

[markroles]

Yeah I've read that article, the one I linked before is the updated version of the ESX3.x version.

I just know vSphere4.0 has improved the iSCSI stack and maybe that's a little better.

Cheers

[jayctd]

They have ... they have also added MPIO which we have tested to add significant IOP increase even when the pipe is not full ...

(We are actually in the same boat evaluating purchasing netapp which will give us both features)

Personally we are leaning toward a conversion to NFS despite adding iscsi MPIO (or possibly a mix) because of the advantages when deduping as well as snaps.

Jered Rassier

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[TimPhillips]

Personally I choosed Starwind. Most of all I liked opportunity of using free version, which only serious limit is 2Tb storage. Working with it already long enought, still got no problems. Even planning to buy commercial version.

[IT_Architect]

Does thin provisioning work on it?

[ConstantinV]

Free edition of our Starwind iSCSI target has some limitations, the most serious of which is 2Tb storage limit. Full product chart you can find here.

Starwind Software Evangelist

[JamesSykes]

I'm seriously considering NFS at the moment too... just wonder how it well it works with high i/o applications like databases. (SQL2008)

Does it compete well against NFS in those scenarios?

[TimPhillips]

In case of databases better to use SAN decision because it uses block-based access, in result giving less network overhead and more perfomance.

[jayctd]

This is a question in our mind too ... something we are going to test heavily. But the white papers show that with the right configuration, load balancing heavy IOP vm's correctly on the stores is also apparently key.

The nice thing is the product we are looking at (netapp) offers both as an option so we can use a mix for the optimal performance mix between the two.

Jered Rassier

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[TimPhillips]

We are currently using software iSCSI target and usual disk array. This optin let us avoid troubles with support of hardware by VmWare products. Moreover we we are using databases and Exchange Server, and in this case iSCSI is the best offer for us.