Index memory usage by GSI Indexes

Currently i have set Index memory as 4GB and index mode as Standard Global Secondary in enterprise edition.
But i would see max index RAM is not using 100% for 4GB. From documentation i have read as Standard GSI can spill to disk when memory runs out. But i don’t see all allocated memory is being used.

What percentage of memory is used in Index Memory.
Do we have any option to set for index to use all index memory allocated.

What is the size of total indexed data? By default, indexer will try to utilize all available memory quota.

Total GSI indexed data --> 2.7 GB

[root@CBS11 CouchIndex]# du -sh @2i/
2.7G @2i/

But from couchbase GUI, we have observed as
Max Index RAM Used%=28.4 and remaining index ram=3.06GB

Index storage is MVCC and there is additional rollback snapshot. The disk usage could be more that actual indexed data. You should look at “data_size” stat in the UI and also “resident_ratio” to get accurate picture of how much is the indexed data and how much of it is currently in memory.

Most of the indexes have 100 cache resident percent. Verified one of index is not having 100% resident and stats below
date size =569 MB
cache resident percent=74.2
In server resource, remaining index ram =1.24 GB