topic Re: De-Dupe volume sizes in ONTAP Discussions

De-Dupe volume sizes

Thu, 05 Jun 2025 07:27:00 GMT

My understanding is that there are limits for the size of volumes that can be de-duped. Is that right? What are those limits and where do they come from?

Thanks!

Dave

Re: De-Dupe volume sizes

Fri, 19 Jun 2009 16:46:57 GMT

It all depends on what version of DATA ONTAP you are running and the model of the filer that you own. For instance we run DOT 7.2.6 with a FAS3020 and the dedupe limit is 1TB volume however if we were to upgrade to 7.3.1 (which isn't in General Deployment yet) we could dedupe a 2TB volume.

Re: De-Dupe volume sizes

Fri, 19 Jun 2009 16:56:11 GMT

Re: De-Dupe volume sizes

sajan — Fri, 19 Jun 2009 18:14:37 GMT

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.

Re: De-Dupe volume sizes

calvarez — Fri, 19 Jun 2009 18:34:01 GMT

NetApp deduplication is the #1 implementation of deduplication on primary storage, meaning it is being used on production systems to deduplicate active data. With well over 30,000 licenses installed, it is a proven technology.

A key factor in the success of NetApp deduplication for primary storage is the fact that the system resources of each storage system model are being considered so that they are not oversubscribed, such as system memory. NetApp deduplication for FAS uses different max volume sizes for different models to help ensure resource availability so that the performance of the primary storage system is maintained.

It is worth noting that this max volume size is a delimiter of the physical size of the volume only. That is to say that even though a volume size may be limited to 3 TB in size, it is still capable of storing greater than 3TB of deduplicated data. For example, you might see 5 TB of data being stored, but it would only be using 2TB of storage thanks to deduplication.

Below are the max vol sizes by model and version of Data ONTAP.

Data ONTAP 7.2.X (Starting with 7.2.5.1) and Data ONTAP 7.3.0
FAS2020	FAS3020 N5200 FAS2050	FAS3050 N5500	FAS3040 FAS3140 N5300	R200	FAS3070 N5600 FAS3160	FAS6030 FAS6040 N7600 FAS3170	FAS6070 FAS6080 N7800
0.5TB	1TB	2TB	3TB	4TB	6TB	10TB	16TB
Data ONTAP 7.3.1 or higher
FAS2020	FAS3020 N5200 FAS2050	FAS3050 N5500	FAS3040 FAS3140 N5300	R200	FAS3070 N5600 FAS3160	FAS6030 FAS6040 N7600 FAS3170	FAS6070 FAS6080 N7800
1TB	2TB	3TB	4TB	4TB	16TB	16TB	16TB

Re: De-Dupe volume sizes

davelightman — Sat, 20 Jun 2009 14:27:39 GMT

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.

Re: De-Dupe volume sizes

radek_kubka — Mon, 22 Jun 2009 08:45:47 GMT

Hi Carlos,

Two things:

NetApp deduplication for FAS uses different max volume sizes for different models to help ensure resource availability so that the performance of the primary storage system is maintained.

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.

For example, you might see 5 TB of data being stored, but it would only be using 2TB of storage thanks to deduplication.

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

Re: De-Dupe volume sizes

jooss — Mon, 22 Jun 2009 12:01:47 GMT

> 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?

The limits come from the available resources on the systems (CPU, memory, etc...).

> Is there any work-around for this?

The limits are volume based so one can break things into multiple volumes. That obviously has some trade-offs in terms of deduplication as well as other areas but is certainly a possibility.

Re: De-Dupe volume sizes

calvarez — Mon, 22 Jun 2009 16:36:07 GMT

The volume size limits help ensure that the actual process of deduplication does not oversubscribe the system resources.

Working with a post-processing deduplication process means that you must take the initial size of the un-deduped data into consideration.

You will need to consider best practices for each specific scenario, as described in TR-3505, mentioned in a previous reply.

Re: De-Dupe volume sizes

amiller_1 — Fri, 26 Jun 2009 21:46:40 GMT

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.

Re: De-Dupe volume sizes

nigelg1965 — Wed, 19 Aug 2009 14:27:59 GMT

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!

Re: De-Dupe volume sizes

radek_kubka — Wed, 19 Aug 2009 14:53:04 GMT

Interesting stuff - we are entering a wild area!

Unfortunately I have no good answer to your question (hopefully someone else does). The only thing on my mind would be to come back to square one & use QSM instead of VSM, which will definitely drop behind all legacy characteristics of the original volume.

What particular error message are you getting when trying to run A-SIS on the new volume?

Regards,
Radek

Re: De-Dupe volume sizes

eric_barlier — Wed, 19 Aug 2009 23:38:44 GMT

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

Re: De-Dupe volume sizes

amiller_1 — Thu, 20 Aug 2009 03:02:03 GMT

Erm...what version of Data ONTap are you running? This restriction was specifically lifted in 7.3.1+ (related to moving the fingerprint hashes from the volume to the aggregate I believe).

Re: De-Dupe volume sizes

christop — Fri, 04 Sep 2009 15:56:10 GMT

Hi:

What is the max flexvol size for deduplication for a GF960 system?

I do not see any guidelines published for this platform.

Thanks,

Chris

Re: De-Dupe volume sizes

tekaravind — Fri, 04 Sep 2009 15:56:53 GMT

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

Re: De-Dupe volume sizes

chriskranz — Fri, 04 Sep 2009 20:32:34 GMT

I don't believe A-SIS is supported on the 900 series.

Re: De-Dupe volume sizes

pascalduk — Mon, 07 Sep 2009 06:16:58 GMT

chriskranz wrote:

I don't believe A-SIS is supported on the 900 series.

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?

Re: De-Dupe volume sizes

tekaravind — Mon, 07 Sep 2009 06:17:53 GMT

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

Re: De-Dupe volume sizes

aarondelp — Tue, 08 Sep 2009 19:46:22 GMT

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