While there are many reasons why some assets are not allocating, the most common is related to the rules used to create your groups.
For example, if you categorize a group by 'AwsAsset - Amazon Asset (EC2 & RDS Instances, S3 Bucket, ELB, CloudFront Dist, Redshift, Route 53 Hosted Zone, ElastiCache Cluster, Kinesis Stream, Lambda Function, SageMaker Endpoint, DMS Replication Instance)' with tag 'owner', you'll get results associated to the above asset types listed as well as gathering related assets. However, not all assets are covered by this search parameter so you may have some assets left unallocated that you would want included. One way to gather the remaining assets is by running the filter rules a second time using 'Amazon Taggable Asset (Does not gather associated assets)' with the same 'owner' tag. This will create another dynamic block of assets which can be merged into the existing block by selecting the check box at the top of both dynamic blocks and give a more complete view of the asset groups. See below for steps regarding how to merge two dynamic groups:
1. Click the open checkbox associated to the header of a dynamic group. This should select all groups
2. Do the same with the second dynamic group so that all groups are now selected as well
3. Click the "Merge dynamic group blocks" button at the top right corner of the right nav:
The newly merged block will look like:
You'll also notice the groups now display both filters when you view them within the "Groups" tab:
For more information regarding perspective building and maintenance, see: Manage Perspective Groups