Merge pull request #77 from ClickHouse/krithika-ch-patch-7

Update cloud-tiers.md

Author: gingerwizard

docs/en/cloud/manage/cloud-tiers.md

@@ -187,6 +187,10 @@ Caters to large-scale, mission critical deployments that have stringent security
 - Offers [HIPAA](../security/compliance-overview.md/#hipaa) Compliance.
 - Exports Backups to the user's account.
 
+:::note 
+Single replica services across all three tiers are meant to be fixed in size (`8 GiB`, `12 GiB`)
+:::
+
 ## Upgrading to a different tier
 
 You can always upgrade from Basic to Scale or from Scale to Enterprise.