I am converting luns from Thin to Thick and the aggregate is now running out of space. There are plenty of luns remaining in Thin provisioning. What is comming to my mind is once luns in Thin provisioning start to increase and claim for more capacity, it will go out of space as well as the volume such as the aggregate. I am not using such kind of snapshots and I am trying to analize my options now.
Once thing that comes to my mind is, once I am converting all to Thick and I never use snapshots, is Fractional Reseve = 100% really necessary?
fractional reserve is not necessary, it only applies to volumes with LUNs in them. The purpose of fractional reserve is to guarantee that no matter what happens with snapshots, they wont take a volume offline. If volume runs out of space it goes offline to protect itself.
Either use fractional reserve 100% or use less, you can even go with 0% as long as you configure snapshot autodelete and set triggers so it happens correctly. This will ensure if snapshots are eating up space before volume goes offline ontap will delete snapshots. There are policies on what snapshots it deletes first but it will delete enough snapshots to keep volume free space enough to keep volume online.
Make decision on what is most important saving space i.e. cost or deleting snapshots this will guide you to decision on fractional reserve 100% or 0%.
The thing is I am not using snapshots and never did. However, is still consumed by 20% of don't know what. If I want to convert a lun to Thick I must double the size of the volume otherwise I wont have space available to do it.