Question about Equallogic snapshots.

Hello forum

I havent been able to confirm this, but do snapshots ever need to commit anything to the base volume?

Lets say i have 10 snapshots and it needs to delete the oldest? will there be a IO load to commit snapshot changes?

Also if anyone could point me at any type of indepth explaination of this snapshot technique I would be interessted to read all about it.

Thanks!