Netapp FAS vs EMC VNX

[ Edited ]


This year we have to decide if we should keep our IBM N-series 6040 (Netapp 3140) stretch metrocluster, upgrade to Netapp 3200 (or rather the IBM alternative) or move to another manufacturer.

And from what I can see, EMC VNX is one of the most serious alternatives. My boss agrees and so we have aranged meeting with EMC to hear about their storage solution including ATMOS.


So, I would like to hear from you other guys what I should be aware about if we decide to go EMC VNX instead of keeping the Netapp/IBM track.

It could be implementation wise or things like "hidden" costs, ie volume based licensing.

I'm having trouble finding EMC manuals to see what can be done and what can't.


Our CIO has set up one big goal for the future user/filestorage: The storage has to cost at most as much as it would if you go and buy a new Netgear/DLink NAS (with mirrored disk) a year.

This would mean that $/MB for the system has to be as close as possible to this goal. Today the cost is at least tenfold more.

Unless we come close to that, we have a hard time convincing the Professors with their own fundings to store their files in our storage instead of running to nearest HW-store and buy a small NAS (or two) for their research team.

It's called "academic freedom" working at a university...

Initial investment might be a little higher, but the storage volume cost has to be a low as possible.


Today we have basic NFS/CIFS volumes, SATA for file and FC for Vmware/MSSQL/Exchange 2007.

No addon licenses except DFM/MPIO/SnapDrive. Blame the resellers for not being able to convince us why we needed Snap support for MSSQL/Exchange.

We didn't even have Operations manager for more than two years and has yet to implement it as it was recently purchased.


The Tiering on Netapp is a story for itself.

Until a year ago our system was IOPS saturated during daytime on the SATA disks and I had to rechedule backups to less frequent full backups (TSM NDMP backup) to avoid having 100% diskload 24/7.

So the obvious solution would be PAM and statistics show that it (512GB) would catch 50-80% of the reads.

But our FAS is fully configured with FC and cluster interconnect cards so there is no expansion slot left for PAM.

So to install PAM we have to upgrade the filer, with all the costs associated BEFORE getting in the PAM.

So the combination of lack of tiering and huge upgrade steps makes this a very expensive story.


What realy buggs me is that we have a few TB fibrechannel storage available that could be used for tiering.

And a lot of the VM images data would be able to go down to SATA from FC.


EMC does it, HP (3Par) does it, Dell Compellent does it, Hitachi does it ...

But Netapp doesn't implement it. Despite having a excellent WAFL that with a "few" modifications it should be able to implement it even years ago.


Things we require are

* Quotas

* Active Directory security groups support (NTFS security style)

* Automatic failover to remote storage mirror, ie during unscheduled powerfailure (we seem to have at least one a year on average).


Things we are going to require soon due to amount of data

* Remote disaser recovery site, sync or async replication.


Things that would be very usefull

* Multi-domain support (multiple AD/Kerberos domains)

* deduplication

* compression

* tiering (of any kind)


So I've tried to set up a number of good/bad things I know and what I've seen so far.

What I like with Netapp/Ontap

* WALF with its possibilities and being very dynamic

* You can choose security style (UNIX/NTFS/Mixed) which is good as we are a mixed UNIX/Windows site.


Things I dislike with Netapp/Ontap/IBM

* No tiering (read my comment below)

* Large (read: expensive) upgrade steps for ie. memory or CPU upgrade in controllers

* Licenses bound to the controller-size and has essentialy to be repurchased during upgrade (this I'm told by the IBM reseller)

* You can't revert a disk-add operation to a aggregate

* I feel a great dicomfort when switching the cluster as you first shut down the service to TRY to bring it up on the other node, never being sure it will work.

* Crazy pricing policy by IBM (don't ask)

* A strong feeling of being a IBM N-series customer we are essentialy a second rate Netapp user.


Things I like so far with VNX from what I can see

* Does most, if not everything our that FAS does and more.

* Much better Vmware integration, compared to the Netapp Vmware plugin that I tried for a couple times and then droped it.

* FAST Tiering

* Much easier smaller upgrades of CPU/memory with Blades


I have no idea regarding negative sides, but being an EMC customer earlier I know they can be expensive, especially after 3 years.

That might counter our goal of keeping the storage costs down.


I essentialy like Netapp/Ontap/FAS, but there is a lot of things (in my view) talking against it right now with Ontap loosing its technological edge.

Yes, we are listening to EMC/HP/Dell and others to hear what they have to say.


I hope I didn't rant too much.

Re: Netapp FAS vs EMC VNX


Please drop me an email to, so I could share my storage selection story with you.

Good luck


Re: Netapp FAS vs EMC VNX


Interesting stuff - I am really keen to see how other members view this.

Few, quick thoughts from me:

Things I like so far with VNX from what I can see

* Does most, if not everything our that FAS does and more.

Actually it doesn't do everything - e.g. there is nothing even remotely resembling MetroCluster functionality you are utilising at the moment (unless I am missing some new EMC functionality I haven't heard about before)

Regarding EMC VNX 'unification' - have you seen this:

* Much better Vmware integration, compared to the Netapp Vmware plugin that I tried for a couple times and then droped it.

Have you seen this in action? Personally I haven't (other than few slides), so I am somewhat skeptical how slick this EMC / VMware integration is. I am using NetApp VSC, and although it isn't perfect, it is very useful in my opinin, most of ther time, it genuinely does what it says on the tin.

* FAST Tiering

Always read the small print . FAST works on 1GB sub-LUN granularity - that's a *lot* of data to mve around! Also it doesn't work on NFS datastores (EMC offers archiving functionality for file shares, which isn't feasible for moving VMDK files around). Also, interestingly enough, EMC introduced so called FAST Cache, which in essence is the same approach as NetApp Flash Cache - it makes me thinking this approach may be actually more feasible that sub-LUN tiering.

* Much easier smaller upgrades of CPU/memory with Blades

I am not familiar with their upgrade process, but again: always read the small print to double-check how convenient this upgrade will be in a real-life scenario! E.g. I know for a fact there is no upgrade path from VNXe to VNX (which not necessarily will be applicable to your case).


Re: Netapp FAS vs EMC VNX

Hi Henry,

Any chances you can post some of your key thoughts here as well?


Re: Netapp FAS vs EMC VNX

FAST not being able to work with NFS is news to me. Good to know and I will ask EMC when we meet them tomorrow. FAST Cache sounds interesting.

Regarding the Vmware plugin I have been checking out what Chad Chakac is presenting on his blog, but of course I will demand a real life view of it ASAP.

Also, I will ask it the blade upgrades realy provide scalability. You might be limited to one CIFS/NFS server only being able to use one blade anyway and not scale with the number of blades.

Regarding the Tiering and movement size, I have been looking at Dell Compellent and are about to visit HP to see 3Par in action.

At least Compellent can move smaller blocks, but it is missing the NAS functionality that we require (unless combined with Microsoft Storage Server solution).

As long as Dell isn't presenting ExaNet soon, I'm not sure it would be the way to go for our enduser files. HP seems to have Windows and Samba-based NAS gateways to the 3Par system.

I'm still not impressed with Netapp's total dismissal of tiering without PAM. They (tiering and PAM) could easily live side by side, both adding value to the Netapp system.

At least in my case the PAM-requirement actualy is one of the reason to make us look the other way instead of keeping the current setup and adding life to the system..

Re: Netapp FAS vs EMC VNX

I'm still not impressed with Netapp's total dismissal of tiering without PAM. They (tiering and PAM) could easily live side by side, both adding value to the Netapp system.

That's actually a very interesting topic in itself. I've mentioned something along these lines few times to different NetApp folks and the answer usually was: "we don't need automated tiering as caching is better". That's arguably not true in every case (e.g. a random write heavy workload), yet EMC following NetApp footsteps with their FAST cache proves the point that the Flex Cache / PAMM concept is doing its job great in many situations.

That being said, from a marketing standpoint having a feature (automated block movement between tiers), even if not using it, is almost always better than not having it!

Re: Netapp FAS vs EMC VNX

Not yet Radek




Re: Netapp FAS vs EMC VNX

Well Dejan let look at the tiering is like the VMotion in the VMWare  it is a nice function to have but if you did not tune it correctly then  you will have too many movement of data at the FAST tiering layer that  will cause you a serious performance issue. I think you might need to reconsider the need of FAST tiering but the Fast Cache is a better option for long run. Well in OnTap 8 you also have the option of using the data motion which allow you to perform the data movement from FC/SAS with out impacting the production system only drawback it will be a manual job.

The thing that impress me is the unisphere that provide a unified view and also execution makes easy for replication, provisioning, backup and DR. The only thing that worries me is the cost that going to impact me as my data grows. There is no saying is the price of the data protection suit is following the controller price or raw data tiering pricing.

Looking back at the Deduplication it only works for the NAS and not for SAN which is not impressive to me but yet this going to be a argument point cause most of the consolidation will happens on NAS area where most of the files being stored. Well on the Ontap 8 you are be able to turn on the compression as well take note it does have performance impact on the vol/lun that you turn it on.

Correct me if I am wrong I just whack thru the VNX documentation i dont think they are having the Metro Cluster solution. they may have the mirror view or netapp snapview equivalent.

Re: Netapp FAS vs EMC VNX

I agree that Tiering inappropriatly used can worsen the situation as a lot of data will be doing ping-pong "in transfer" between tiers.

Also, FAST without FASTCache could make you having quite slow system until next rearangement in the tiers when the accessed data is moved up, by then the target data might be "uninteresting" until next week, month etc...

Looking at the FASTCache more closely it seems to be the right combination with tiering on SAS/SATA level.

The granularity FASTCache operates at 64K block level, making it decent sizewize, compared to FAST 1GB granularity.

Now compare that to DataMotion granualrity of whole volume, never ranging less than a few hundred GB and probably getting closer to TB size.

And you don't move ie. the volume with the whole Sharepoint database disk to a slower tier just because 90% is static data.

So the DataMotion is more useful (for me) in situations where I wish to rebalance aggregates or move data from aggregates to replace aging/small disks

What does worry me regarding any kind of tiering is ie. the location of file's metadata.

Much, if not most, of the pressure on my SATA-disks is metadata-access.

I'm a little worried that metadata will "pull along" data filling the cache, depending on the actual location of metadata on ie. VNX.

While Netapp PAM can be configured to cache only metadata, but I haven't seen any configuration to prioritize metadata when replacing the PAM content.

EMC FASTCache "detailed review" paper :

Message was edited by: dejan-liuit Added EMC link

Re: Netapp FAS vs EMC VNX

Just my biased 2 cents :-)

NetApp (FAS32xx) pro's:

* Room for 50% more IO cards compared to FAS3140 / N6040

* 6Gbps SAS with new DS2246 shelf (remember 4x 6Gbps lanes in a SAS cable)

* vfilers for multiple domains

* Free deduplication

* Free compression (inline, as with almost all things inline, it can impact performance)

* Free My Autosupport/upgrade advisor (only available for N Series customers if they go through IBM support)

* Flash cache is dedup aware, works at 4kb block level, set it & forget it.

* Plenty of snapmanagers to pick from.

* IBM always lags behind with new software versions for the N Series: snapmanagers, ontap versions

EMC VNX con's:

* Deduplication at the file level, not block level

* Deduplication only on CIFS/NFS, but not for: VMware/Oracle over NFS.

* No metrocluster functionality

* Different replication techniques for block/file, each with its own limitations !!

* Big performance impact with raid6 over raid5.

* VNX means: multiple operating systems to learn !

* FAST cache can have a big performance impact (moving data around)

* Unisphere is nice, but ask EMC what other software you might need, based on features you want to use.

* Entry level VNX5100 is FC only, and you can't upgrade.

In the end a consumer grade NAS will always have a much lower price per GB.

But I don't think I need to elaborate on why you don't want that in an enterprise environment.

Hope this helps.