If the deduplication limit (for system) is exceeded:
1. If the dedupped zfs resides in a pool with SSD read cache, it's not affected.
2. If the dedupped zfs resides in a pool without SSD read cache (where the DDT in this case is stored in the system RAM cache), the dedup feature for this zfs will be automatically disabled and cannot be enabled again. All later-stored data will be stored with standard non-dedupped manner and therefore cause the zfs to become a hybrid instant with both dedupped and non-dedupped data inside.