aggr options nosnap=on

[mdvillanueva]

Hi Experts,

This may be a dumb question.. Can I turn off the "nosnap=on" option in one of our aggregate? I have one aggregate that is showing that option. We don't take a snapshot of the aggregate and I want all our aggregates to be uniform in settings. What impact would turning that option bring?

Thanks,

Maico

[AGUMADAVALLI]

Hi there,

If you are sure you don't want the aggr snapshots, you can surely use the options(nosnap=on), but the best practice is if it is root volume, please make sure the aggregate snapshots occur atleast once a day and snap reserve on the aggregate can be minimum to 5%.

If you have snapmirror enabled on the volumes of the aggr (referred), it is safe to set nosnap to on.

thank you,

AK G

[mdvillanueva]

The fact that only one of our aggregates have that option means most of our aggregates has aggregate snapshot capability on.

I just want to know if turning nosnap to off will do any harm on the aggregate.

[aborzenkov]

Actually 8.x sets root aggregate snapshot reserve to 0% by default. Could you give reference to best practice document you mention where it recommends 5% for root aggregate?

[scottgelb]

Most customers didn't notice the change but do notice more the larger size of root needed for 8.x Agreed the Root aggr reserve is 0 and non root have an aggr reserve on new installs. Haven't heard a best practice either to use aggr snaps or a reserve on root. There could be a conflicting doc or kb out there that would be good to see if it does mention that.

I like keeping a snapmirror of the root volume local on a system with more than one aggr then that mirror can be broken and marked as root if root ever fails. A Remote copy is good too. Similar to what we do with vsroot load sharing mirrors in Cluster-mode and works well for vol0 in 7-mode too. If you have he space though since larger in 7-mode for a whole root volume as opposed to a 20mb mroot

[mdvillanueva]

Scott,

Do you use aggr snap in your environment? I perform a Snapvault of the root volume to another filer already. Is that enough?

[scottgelb]

Unless you need different retention why not snapmirror? For as little as root changes except for logs mirror with local snaps fits the ticket. I leave new installs with 0 on root aggr reserve but am interested if a doc does say not too. Best practice is 0 now on a dedicated root aggr. But lots of kbs and docs out there.

[AGUMADAVALLI]

There is no affect as i said, just leave it on for the root aggregate.

You should be fine.

thank you,

AK G

[JIULING_SHENHUA]

Hi,

The aggregate will can not take the snapshot only, no other affect.

THKS

Jiuling Xu

[LTDCLSERGAO]

Hello,

yes you can turn this options to off, and if you want to be sure that no snap will be taken, you can set the snap reserve and snap sched to 0 for this agregat.

[nick_walford]

One reason you might turn off aggregate snaps is for a Flash Pool/Hybrid aggregate, as stated in TR-4070:-

5.4 Aggregate Snapshots

Aggregate Snapshot copies should be disabled and existing aggregate Snapshot copies should be deleted before enabling Flash Pool on an existing aggregate. Aggregate Snapshots copies should not be enabled on a newly created Flash Pool.

Regards,

NickW