The Dell XtremIO Deploy Achievement documents specify different numbers for the maximum volumes in various contexts. However, for the XtremIO Consistency Group, the supported and QA certified number of volumes is 512. This is based on the authoritative information provided in the official release notes and support documents from Dell. It's important to note that while there may be higher numbers mentioned in some technical documents or API responses, such as 60000 or 32000, these are either not recommended or pertain to different aspects of the XtremIO system, not specifically to the Consistency Group1.