topic Re: aggregate snap reserve size in ONTAP Discussions

aggregate snap reserve size

slava — Thu, 05 Jun 2025 07:28:12 GMT

Hello guys,

I would like to know what is the minimal aggregate snap reserve size i may left on the system?

Re: aggregate snap reserve size

tyeoman_swinton — Mon, 11 May 2009 10:33:39 GMT

Hi,

I've reduced this to 2% before, but be very careful with reducing aggr snap reserve as it gets used for a few different things. One example is semi-sync SnapMirror where it is used as a buffer.

Re: aggregate snap reserve size

slava — Mon, 11 May 2009 10:48:00 GMT

Thank you Yeoman,

In my case there are no any snapmirror at all.

Slava Chubar

Professional Services Engineer

NetApp

972.3.9205538 Direct

972.52.3120538 Mobile

slava@netapp.com

www.netapp.com

Re: aggregate snap reserve size

pascalduk — Mon, 11 May 2009 12:23:17 GMT

If you don't have RAID syncmirror and / or a metrocluster configuration and you don't expect to use aggregate snap restores (has anyone ever used this???), you don't need snapshots on aggregate level and therefore can set the aggregate snap reserve to 0%. If you use aggregate snapshots set the snap reserve to such a level that you normally don't run of reserve space.

We are running on all our non metrocluster configurations with 0% aggregate snap reserve and no aggregate snapshots (snap sched -A <aggregate> 0) ever since we migrated to ontap 7.0.

Re: aggregate snap reserve size

slava — Mon, 11 May 2009 12:49:30 GMT

Thank you Dukers,

As I know, you need to save some space for some maintenance processes like block reallocation or in case of aggr inconsistence when you need to run wafl_check.

Slava Chubar

Professional Services Engineer

NetApp

972.3.9205538 Direct

972.52.3120538 Mobile

slava@netapp.com

www.netapp.com

Re: aggregate snap reserve size

amiller_1 — Tue, 12 May 2009 19:40:31 GMT

I wouldn't go below 3% aggregate snap reserve (that does let you get back 2% from the default at least) as doing otherwise can cause data corruption issues (as well as cause issues upgrading to 7.3.x).

See this bug report as well....

http://now.netapp.com/NOW/cgi-bin/bol?Type=Detail&Display=164329

There was also a general warning in the 7.3.x upgrade docs about this as well giving 3% as a minimum.

I would stay away from 0% aggregate snap reserve as I have personally had data corruption issues with this (a volume with "file" space guarantee got set to "none" silently and subsequently had some corrupted files which we didn't notice for a couple months due to some odd circumstances).

Re: aggregate snap reserve size

pascalduk — Wed, 13 May 2009 09:07:31 GMT

The bug is not about snap reserve size for the aggregate, but about free space in the aggregate. Using a snap reserve of more than 0% is only a tool to make sure nothing can ever take up all the space in an aggregate.

I always have at least 10% free in the aggregate, therefore for me this will never be an issue. But if I am wrong I would really like to know about it.

Re: aggregate snap reserve size

evilensky — Sun, 28 Feb 2010 20:30:33 GMT

This thread is a top Google result for "aggregate snap reserve"

Have you come across any contrary information?

Re: aggregate snap reserve size

jayadratha — Mon, 01 Mar 2010 07:23:29 GMT

Hi, we always leave default 5%.

And disabling aggr snap reserve only with metrocluster configuration or when extra space needed (not best practice but...).

http://now.netapp.com/NOW/knowledge/docs/ontap/rel727_vs/html/ontap/sysadmin/provisioning/concept/c_oc_prov_sys-maintenance-aggr-snapshot-copy-managing.html#c_oc_prov_sys-maintenance-aggr-snapshot-copy-managing

Best practice for us is at least 10% free space in aggregate.

Re: aggregate snap reserve size

pascalduk — Mon, 01 Mar 2010 07:30:31 GMT

There is no right or wrong here, just do what makes you comfortable.

If you don't use aggregate snapshots, there is no need to to reserve space in the aggregate. But some use the snap reserve as a tool to make sure there is always (enough) free space in the aggregate.

Re: aggregate snap reserve size

mheimberg — Wed, 03 Mar 2010 08:33:12 GMT

jayadratha schrieb:

And disabling aggr snap reserve only with metrocluster configuration

This is definitely wrong: The MetroCluster uses SyncMirror and this in turn uses aggregate snapshots:

"...However, SyncMirror aggregates use snapshots to optimize plex resynchronization...."

MetroCluster is the one configuration where one should absolutely *not* disable aggr reserve (set to 0%).

Markus

Re: aggregate snap reserve size

jayadratha — Wed, 03 Mar 2010 08:59:48 GMT

Hi!

I need to say "disable automatic aggr snapshot creation by scheduler".

Because sycmirror don't use this aggr snapshot copy.

Re: aggregate snap reserve size

mheimberg — Wed, 03 Mar 2010 09:19:52 GMT

I need to say "disable automatic aggr snapshot creation by scheduler".

Because sycmirror don't use this aggr snapshot copy.

Yes, this way I completely agree

So it will be:

snap reserve -A aggr0 5

snap sched -A aggr 0 0 0

aggr options aggr0 nosnap on

regs

Markus

Re: aggregate snap reserve size

aborzenkov — Mon, 08 Mar 2010 05:54:51 GMT

http://now.netapp.com/NOW/cgi-bin/bol?Type=Detail&Display=164329

I must honestly admit I fail to understand what exactly was fixed. Bug description visible to me sounds like deliberetae design decision. Do you have any details (i.e. what exactly was changed in a "fix")?

Re: aggregate snap reserve size

mikesicarup — Mon, 28 Mar 2011 20:52:12 GMT

I asked a NetApp instructor about this, and besides the Synch mirror, the aggr snapshots are leveraged by WAFL check and WAFL iron. He indicated that if you need to run these utilities, not having aggr snapshots would take days as opposed to hours. It made me take pause.

Re: aggregate snap reserve size

DRUMDUDESAN — Thu, 23 May 2013 21:23:06 GMT

Hi,

Can we get an update on from NetApp themselves on this please running NetApp Release 8.1x and above.

What is aggregate snap reserve required for?

What are the implications of setting snap reserve on an aggregate to 0% that does not hold DataOntap/vol0?

Thanks

Jeff

Re: aggregate snap reserve size

adaikkap — Fri, 24 May 2013 07:06:31 GMT

Hi Jeff,

vol0 is on an aggr and not on the snapreserve of an aggr.

Regards

adai

Re: aggregate snap reserve size

DRUMDUDESAN — Fri, 24 May 2013 16:42:55 GMT

Hi Adai,

You have not understood the question and the post thread.

Re: aggregate snap reserve size

thomas_glodde — Fri, 24 May 2013 21:17:03 GMT

Aggregate snapshot reserve is only needed in metrocluster configurations, its set to 5% then.

in all other configurations you can drop it to 0%, its even the new default for ontap 8.1 and beyond.

Re: aggregate snap reserve size

DRUMDUDESAN — Mon, 27 May 2013 14:59:41 GMT

Hi,

Where is this located in the documentation or recent TR document?

Thanks for your response.

Jeff