Information on volume sizes for all supported platforms with various Data ONTAP versions is available in Dedupe DIG: http://media.netapp.com/documents/tr-3505.pdf.

Thanks, Carlos!

A couple of follow up questions:

Where do these limits come from and why do they vary from system to system? For example, why is the limit 4TB on the FAS 3140 and 16TB on the FAS 3170?

Is there any work-around for this? For example, if I have a bunch of VMware boot images that would de-dupe down to 5TB of real disk space is there any way to do that (on a FAS 3140)? If the data that's common between images is about 1TB each, it would be a shame to have to duplicate that data a bunch of times due to this limit.

Hi Carlos,

Two things:

Does it relate to system resources during actual de-duplication or outside of this process? The former may or may not be a problem, as in a non-24/7 environment hammering the system for say 8 hours only to de-dupe the data could be 100% feasible. The latter is a subject to discussion in two separate threads here & I am yet to hear a firm answer to this.

Well, nice. The problem is A-SIS is a post-process deduplication, so if above scenario happens on one of the smaller filers, it may mean repetitive adding the un-de-duped data to the volume, running A-SIS against it, adding more data & so on, so forth. A bit tedious & not every admin will have enough time / patience to actually do this.

Do not get me wrong - I love A-SIS, but what I am saying is that capping volume sizes can make people's life harder, so the question is whether there is a good reason behind that.

Regards,
Radek

Why then can't you run A-SIS on a volume that was ONCE over the limit. We migrated from 3020 with a main volume of c. 4.5Tb to a 3140 with new shelves, and in the process I split the data across two different volumes, using Snapmirror, so as to be able to use A-SIS, unfortunately as you can't retrofit Qtrees we had to Snapmirror an entire volume and then delete the unwanted parts. All resulting volumes are well below 3TB, but A-SIS will not work on the volume that was briefly over 4TB or indeed a completely fresh copy of it!

hi Nigel,

Did you consider using QSM to mirror qtrees into volumes that would maybe solve this? I know I have not got enough information about this to make

a qualified statement, and its probably too late as well. but for the future maybe QSM would be good for you?

Cheers,
Eric

Perfect graph....I've found this information in multiple places but that's the nicest representation so far.

And with 7.3.1+, it's ever so much less painful given being able to shrink a volume back down under the limit to turn on dedup.

Hello,

I am on leave till Monday, 7th September 2009. Please contact support@tek-tools.com for any assistance in the meantime, and I will attempt to respond to your email as soon as possible upon my return.

Regards,

Aravind

Correct, but the R200 is supported which basically is  900 series hardware. Could it perhaps be that ontap software can't handle the nearstore personality license, which is required for the a-sis license, on the 900 series?

A couple of things.  Dedupe is not SUPPORTED on the 7.2 code line but it will run.  I have a 940 in my lab and it works fine.  As of the 7.3 code line the functionality was disabled.

As to why you can't dedupe a volume once it goes over the limit.  You can't (and the reason why it doesn't make any sense) is because it is a bug.  I think that the bug was fixed in 7.3 but I'm not sure.  I know that bug existed in 7.2.

Regards,

Aaron

Sorry for the confusion Andrew - my comment was dedupe on the 9XX FAS series.  It is supported on everything else obviously! 

I could be wrong on that one but that is what I was told by somebody at NetApp the other day, I haven't ever had a need to verify if the support statement is true for the 900 series.  If it isn't, please let me know!

Thanks!

So....I'm horrendously late replying here....but you're right -- I didn't catch the reference to the 9xx line.

So...I'll bow to your technical superiority. (this time at least )

That's a very good question. My (informed) guess is 3TB.

Here is why I think so:

http://now.netapp.com/NOW/knowledge/docs/ontap/rel732_vs/html/ontap/smg/GUID-7ED7077A-26E6-425A-B00E-E072FD7547F0.html

The title says "Operational limits for FlexClone files and FlexClone LUNs", but if you read carefully there is also this:

"Note: The block-sharing mechanism used by FlexClone files and LUNs is also used by deduplication."

Regards,

Radek

Ok, great to know.

Thanks for your help.

Regards,

Pascal