# Use share identifiers to identify workloads
<a name="share-identifiers"></a>

You can use share identifiers to tag jobs and differentiate between users and workloads. The AWS Batch scheduler tracks usage for each share identifier by using the `(T * weightFactor)` formula, where *`T`* is the vCPU usage over time. The scheduler picks jobs with the lowest usage from the share identifier. You can use a share identifier without overriding it.

**Note**  
Share identifiers are unique within a job queue and are not aggregated across job queues. 

You can set fair-share scheduling priority to configure the order that jobs are run in on a share identifier. Jobs with a higher scheduling priority are scheduled first. If you don’t specify a fair-share scheduling policy, all jobs that are submitted to the job queue are scheduled in FIFO order. When you submit a job, you can’t specify a share identifier or fair-share scheduling priority.

**Note**  
Attached compute resources are allocated equally among all share identifiers unless explicitly overridden.