Metro volume was initially introduced in PowerStoreOS 3.0 for the VMware environment. With PowerStoreOS 4.0, its capabilities have been expanded to include various Linux operating system versions and configurations. PowerStoreOS 4.0 adds the support of SCSI-3 reservations and registrations for Metro Volume, enabling it to be used in a standalone Linux host and clustered Linux hosts configuration. PowerStore manages the synchronization of data and SCSI reservations across PowerStore clusters. In addition, PowerStoreOS 4.0 allows grouping several volumes into a single Metro Volume Group, allowing them to be managed in a logical unit.
The previous sections, Metro Volume and Witness, lay the groundwork for understanding Metro Volume, detailing its functionality, operation, and various failure protection scenarios. It is recommended to familiarize yourself with this information. This section focuses on the interactions and ALUA states of Metro Volumes on Linux.
Metro Volume is a storage-level feature that requires no modifications to the Linux hosts or applications. It is a stretched volume spanning across two PowerStore clusters. Each Metro Volume consists of two volumes, one on each cluster, synchronized bi-directionally over a replication network.