1. ACM 2.7 had finished perf tests for a hub managing 3510 SNOs clusters and the numbers for restore is very high compared with the backup
   Scenario: 

• Backup all ACM resources, time to backup about 4min ( 28202 resources )
• Run a restore on the same hub, restoring the above backup ( so all resources already exist, they are just updated and tagged with the restore label) : 1h12min - this time is too high.. especially since this restore is executed on a passive hub and would be re-run as soon as new backups are available

To simplify the tests I run a simplified set of perf tests :
    - created ~32705 secrets

• backup then restore them

Results for restore are listed below

1. Ask to update existing (existingResourcePolicy: update)

• • update existing
    apiVersion: velero.io/v1
    kind: Restore
    metadata:
     creationTimestamp: '2023-01-04T22:08:47Z'
     generation: 4895
     managedFields:
      - apiVersion: velero.io/v1
       fieldsType: FieldsV1
       fieldsV1:
        'f:spec':
         .: {}
         'f:backupName': {}
         'f:existingResourcePolicy': {}
       manager: Mozilla
       operation: Update
       time: '2023-01-04T22:08:47Z'
      - apiVersion: velero.io/v1
       fieldsType: FieldsV1
       fieldsV1:
        'f:spec':
         'f:excludedResources': {}
         'f:scheduleName': {}
        'f:status':
         .: {}
         'f:completionTimestamp': {}
         'f:phase': {}
         'f:progress':
          .: {}
          'f:itemsRestored': {}
          'f:totalItems': {}
         'f:startTimestamp': {}
       manager: velero-server
       operation: Update
       time: '2023-01-04T23:32:43Z'
     name: 1-update-restore-acm-credentials-schedule-20230104205535
     namespace: open-cluster-management-backup
     resourceVersion: '845146'
     uid: eaafc392-5ea7-4418-a51b-eabbea353ed8
    spec:
     backupName: acm-credentials-schedule-20230104205535
     excludedResources:
      - nodes
      - events
      - events.events.k8s.io
      - backups.velero.io
      - restores.velero.io
      - resticrepositories.velero.io
     existingResourcePolicy: update
     scheduleName: acm-credentials-schedule
    status:
     completionTimestamp: '2023-01-04T23:32:43Z'
     phase: Completed
     progress:
      itemsRestored: 32694
      totalItems: 32694
     startTimestamp: '2023-01-04T22:08:47Z'

2.  * do not update existing

apiVersion: velero.io/v1
kind: Restore
metadata:
 creationTimestamp: '2023-01-04T21!https://emoji.slack-edge.com/T030G10V24F/00/72db96a6f75c0f77.png!47Z'
 generation: 3267
 managedFields:
  - apiVersion: velero.io/v1
   fieldsType: FieldsV1
   fieldsV1:
    'f:spec':
     .: {}
     'f:backupName': {}
   manager: Mozilla
   operation: Update
   time: '2023-01-04T21!https://emoji.slack-edge.com/T030G10V24F/00/72db96a6f75c0f77.png!47Z'
  - apiVersion: velero.io/v1
   fieldsType: FieldsV1
   fieldsV1:
    'f:spec':
     'f:excludedResources': {}
     'f:scheduleName': {}
    'f:status':
     .: {}
     'f:completionTimestamp': {}
     'f:phase': {}
     'f:progress':
      .: {}
      'f:itemsRestored': {}
      'f:totalItems': {}
     'f:startTimestamp': {}
   manager: velero-server
   operation: Update
   time: '2023-01-04T21:56:49Z'
 name: 1-restore-acm-credentials-schedule-20230104205535
 namespace: open-cluster-management-backup
 resourceVersion: '679645'
 uid: 40c01523-a098-42b4-a204-c28e4f43450d
spec:
 backupName: acm-credentials-schedule-20230104205535
 excludedResources:
  - nodes
  - events
  - events.events.k8s.io
  - backups.velero.io
  - restores.velero.io
  - resticrepositories.velero.io
 scheduleName: acm-credentials-schedule
status:
 completionTimestamp: '2023-01-04T21:56:49Z'
 phase: Completed
 progress:
  itemsRestored: 32694
  totalItems: 32694
startTimestamp: '2023-01-04T24: 00 : 47Z'

3.  * clean restore ( no data on hub )

apiVersion: velero.io/v1
kind: Restore
metadata:
  creationTimestamp: '2023-01-05T00:18:29Z'
  generation: 1636
  managedFields:
    - apiVersion: velero.io/v1
      fieldsType: FieldsV1
      fieldsV1:
        'f:spec':
          .: {}
          'f:backupName': {}
          'f:existingResourcePolicy': {}
      manager: Mozilla
      operation: Update
      time: '2023-01-05T00:18:29Z'
    - apiVersion: velero.io/v1
      fieldsType: FieldsV1
      fieldsV1:
        'f:spec':
          'f:excludedResources': {}
          'f:scheduleName': {}
        'f:status':
          .: {}
          'f:completionTimestamp': {}
          'f:phase': {}
          'f:progress':
            .: {}
            'f:itemsRestored': {}
            'f:totalItems': {}
          'f:startTimestamp': {}
      manager: velero-server
      operation: Update
      time: '2023-01-05T00!https://emoji.slack-edge.com/T030G10V24F/46/022dacef2450ff96.png!40Z'
  name: 1-clean-hub-restore-acm-credentials-schedule-20230104205535
  namespace: open-cluster-management-backup
  resourceVersion: '1010580'
  uid: 1fa43d2b-07a8-410f-9477-eafd3cecc0ea
spec:
  backupName: acm-credentials-schedule-20230104205535
  excludedResources:
    - nodes
    - events
    - events.events.k8s.io
    - backups.velero.io
    - restores.velero.io
    - resticrepositories.velero.io
  existingResourcePolicy: update
  scheduleName: acm-credentials-schedule
status
  completionTimestamp: '2023-01-05T00: 46 : 40Z'
  phase: Completed
  progress:
    itemsRestored: 32694
    totalItems: 32694
  startTimestamp: '2023-01-05T00:18:29Z'