topic Re: Dedupe gains, now what? in ONTAP Discussions

Dedupe gains, now what?

eric_barlier — Thu, 05 Jun 2025 07:25:10 GMT

All,

We are deduping a Vmw. environment and so far we ve got 12TB back. Now a couple of questions arise:

1. How much of the 12TB is wise to start using? I know this question has got a "how long is a piece of string" connotation

to it, but any experiences anybody would like to share?

2. The next question is: How do we monitor how this gained space is being used? OM (3.7) does not seem to allow for it.

We have got our vols and LUNs setup so all free blocks go back to aggr. for easy of management, but IS there a way of

keeping track of how its used?

I guess if I give this some thinking we could create new vols we for non-prod. that we could claim back fast if needed and monitor

aggr. space usage? any other ideas?

Finally, a bit off topic: I know we can dedupe Vfilers from 7.3 and onwards, but have anybody actually turned on SIS on volumes (on vfiler0) that

are owned by Vfilers in 7.2 and had that work?

Cheers,

Eric

Re: Dedupe gains, now what?

raja — Tue, 04 Aug 2009 02:19:43 GMT

Hi,

2. The next question is: How do we monitor how this gained space is being used? OM (3.7) does not seem to allow for it.

We have got our vols and LUNs setup so all free blocks go back to aggr. for easy of management, but IS there a way of

keeping track of how its used?

This is available in OM 3.8.

See

http://communities.netapp.com/message/13742#13742 or

http://communities.netapp.com/message/13128#13128 for some details.

Thanks,

Raj.

Re: Dedupe gains, now what?

eric_barlier — Tue, 04 Aug 2009 02:48:18 GMT

Thanks for that. That will facilitate me asking for a new DFM server 😉

Eric

Re: Dedupe gains, now what?

radek_kubka — Tue, 04 Aug 2009 10:56:11 GMT

1. How much of the 12TB is wise to start using?

Hi Eric,

My thoughts around this one - http://communities.netapp.com/message/13806#13806

Regards,
Radek

Re: Dedupe gains, now what?

amiller_1 — Wed, 05 Aug 2009 01:11:32 GMT

Agreed on dedup reporting in 3.8 (although there are some additional feature requests around it, it is there).

The first thing I thought of though around VMware and dedup is.....using NFS. Given being very proficient with thin provisioning (something not many people are ), there's not a huge practical difference....but the manageability and visibility up at the VMware level of the deduped/free space is very nice.

Re: Dedupe gains, now what?

amiller_1 — Wed, 05 Aug 2009 01:12:03 GMT

And....hopefully you can just upgrade the existing DFM server (3.8 isn't all that much heavier than 3.7).

Re: Dedupe gains, now what?

eric_barlier — Wed, 05 Aug 2009 04:48:02 GMT

Hi Andrew,

One of the big differences from a management point of view is that you can grow/shrink your filesystem on the fly with NFS. If using LUNs you d

have to vstorage motion in and out. Thats quite handy.

on a another note, being lazy, I thought I d ask the following here. Im debating with a colleague which insists I ask others:

snap name date action

weekly.0 Sun 7.1-09 > my.txt will not occur in this snapshot.

daily.0 Sun 7.1-09

daily.1 Sat 6.1-09

daily.2 Fri 5.1-09

daily.3 Thu 4.1-09

daily.4 Wed 3.1-09 > my.txt deleted

daily.5 Tue 2 1-09

daily.6 Mon 1.1-09 > my.txt created

1.1-09: I create my.txt file

3.1-09: I delete my.txt file

7.1-09: I take my first weekly.0 after daily.0.

Statement: my.txt cannot be retrieved from weekly.0

yes or no.

Re: Dedupe gains, now what?

radek_kubka — Wed, 05 Aug 2009 08:42:52 GMT

Hi Eric,

I am not getting your timeline (isn't it in reverse order?), yet the bottom line is simple:

Any snapshot preserves live file system state at the moment of taking the snapshot, so if a file didn't "exist" at that point in time, there is no way it can be retrieved from that snapshot.

All the names - hourly, daily, weekly - are just for housekeeping purposes as they reflect the default retention period. Having said that, there is nothing stopping you from deleting weekly.x snap just after 5 minutes.

Regards,
Radek