topic Re: Reallocate 800GB LUN with Snapshots in ONTAP Hardware

Reallocate 800GB LUN with Snapshots

andreas_koeller — Thu, 05 Jun 2025 07:15:21 GMT

Hi Folks,

i want to reallocate a LUN in our FAS3020 SAN.

The lun is 800GB big.

What about the alleady existing Snapshots after the reallocate?

How big will be the next Snapshot after reallocateing the lun?

Can i do the reallocate step by step? i.e. 10 Minutes Reallocate then stop an the next day go on?

Which command should i use for reallocating the lun?

Regards,

Andreas

Re: Reallocate 800GB LUN with Snapshots

radek_kubka — Mon, 19 Apr 2010 11:36:07 GMT

Hi and welcome to the forums

Short answer - have a look at reallocate manual on http://now.netapp.com/NOW/knowledge/docs/ontap/rel732_vs/html/ontap/cmdref/man1/na_reallocate.1.htm. The actual switch you should be looking at is -p:

Using the -p option may reduce the extra storage requirements in a flexible volume when reallocation is run on a volume with snapshots. It may also reduce the amount of data that needs to be transmitted by SnapMirror on its next update after reallocation is performed on a SnapMirror source volume.

Long answer - type "reallocate" in search box here on communities & go through the results. This thread is absolutely priceless in my opinion & gives you tons of information:

http://communities.netapp.com/message/20969#20969

Another one, nice example from the field about the practical impact of fragmentation & reallocation:

http://communities.netapp.com/thread/7456

Hope it helps.

Regards,

Radek

Re: Reallocate 800GB LUN with Snapshots

peluso — Mon, 10 May 2010 20:18:15 GMT

Thanks radek for responding!

I moved this thread to the product & Solutions area within the community to give expand the visibilty for the question.

Terri