A datastore is a collection of virtual volumes. In ABS, datastores and storage policies are coupled; all virtual volumes in a datastore share the same storage policy.
Storage-related resources in AVE include virtual volumes associated with virtual machines, virtual volume snapshots, VM snapshots, and ISO images. All of these resources correspond to storage objects in ABS. However, these storage objects are managed independently by ABS and cannot be automatically detected or directly used by AVE unless they are actively imported into AVE (which effectively means they are recorded in AVE's MongoDB). The relationship is illustrated in the diagram below:
In AVE, you only need to focus on compute workloads, without worrying about which ABS datastore a storage resource belongs to. However, in ABS, datastores and storage policies are coupled, and exposing storage policy as a datastore attribute would introduce unnecessary complexity for AVE users. To simplify operations, AVE introduces its own concept of "storage policies." AVE manages virtual volume creation through storage policies at its own layer, which determines the datastore a virtual volume is placed in.
Currently, AVE storage policies support only iSCSI datastores by default. Datastores can be automatically created or deleted as needed, allowing you to focus on the compute layer. You can create different storage policies in AVE based on your business requirements.
In addition to name and description, AVE storage policies support the following options, divided into basic policies and advanced policies.
AVE provides a default storage policy named "default" with the following settings: number of replicas: 2, thin provisioning: Yes, number of stripes: 8, stripe size: 256 KiB.
Automatic virtual volume management is a key component of AVE storage policies. When creating a virtual volume, you only need to specify the storage policy. AVE creates the virtual volume according to the specified storage policy and automatically places it in a datastore that matches the policy.
In AVE, each storage policy has one or more corresponding iSCSI datastores. Because a single iSCSI datastore can hold a maximum of 256 LUNs, when the LUN limit is reached for all available iSCSI datastores under a given policy, AVE automatically creates a new iSCSI datastore for that storage policy and places the new virtual volume in it. When a virtual volume is deleted, AVE actively reclaims the LUN ID under its corresponding iSCSI datastore, making it available for future virtual volume creation.
