Why is the FlexGroup size so large after creating an S3 bucket?
Applies to
- ONTAP 9.8+
- FlexGroup
- S3 Bucket
Answer
In ONTAP, the underlying architecture for a bucket is a FlexGroup volume—a single namespace that is made up of multiple constituent member volumes but is managed as a single volume.
In 9.7, a S3 bucket was associated with a FlexGroup. Hence whenever a bucket was created, a new Flexgroup was created underneath, which was the same size as that of the bucket size. The bucket could be created either by specifying aggr-list during bucket create command (in which case those aggregates are picked for provisioning of FlexGroup) or by using auto-provision.
From 9.8 onwards, a bucket is associated with a Qtree, enabling us to have multiple buckets on a FlexGroup. The idea here is to have a large size FlexGroup on which multiple buckets can be placed, and the provisioning of FlexGroup is done through Balanced Placement.
When the first bucket is created, a large size FlexGroup gets created. After this, when the following buckets are created, they can either be placed on an existing FlexGroup (if they meet the criteria) or they would be placed on a new FlexGroup that would be created as a part of bucket creation. Several criteria are considered while deciding whether to place the bucket on an existing Flexgroup or create a new FlexGroup.