Hi Javier,
Thank you for contacting NetApp community, When you first take a snapshot, it occupies no space as it just a copy of the metadata of the volume. but still you can recover any data from that respective volume assuming the underlying disks/aggregate is healthy.
Remember, after a snapshot no block that exists at that time can be altered as changes are reflected in new blocks (data or metadata). The space consumed by a snapshot will be the amount of 4KB blocks that are changed over the life of that snapshot. Therefore at this point no one can actually predict how much space your snapshot may consume but in case you are concerned volume running out of space i recommend to use snap autodelete feature where if your volumes reaches a threshold limit set by you it will automatically starts deleting older snapshots first to reclaim space. So i suggest if you wanna give a try then set autodelete option and create a snapshot and monitor the growth and decide if you want to continue with snapshots ?
Thanks,
Nayab
