Hitachi TrueCopy® (TC) provides a continuous, nondisruptive, host-independent remote data-replication solution for disaster recovery or data migration purposes.
Using UCP Advisor, you can create and maintain mirror images of production volumes at a remote location. This lets you create a remote copy of primary site or production data that is automatically updated for executing test and development tasks, or for operations against production data.
The TrueCopy primary storage system contains the primary volume (P-VOL) of a copy pair, and the secondary storage system contains the secondary volume (S-VOL). When the primary storage system accepts a write operation for a P-VOL, the data is written on the primary volume and then sent by the primary storage system to the secondary storage system. Subsequent write operations are not accepted by the primary volume until acknowledgement is received from the secondary storage system for the previous write operation, ensuring that the data in the secondary volume stays synchronized with the primary volume.
The primary volumes (P-VOLs) on the primary storage system are copied to the secondary volumes (S-VOLs) on the secondary system. The P‑VOLs contain the original data, and the S‑VOLs are the mirrored volumes that contain the backup or duplicate data.
A consistency group is a group of pairs on which copy operations are performed simultaneously and in which the status of the pairs remains consistent. A consistency group can include pairs that reside in up to four primary and secondary systems.
You can issue a TrueCopy command to a consistency group to perform the operation on all pairs in the group at the same time. The status of the pairs changes at the same time, though this depends on the group options you have set. Some pair operations take priority under certain circumstances.
The following figure shows a typical TrueCopy environment.
For more information about TrueCopy on Hitachi storage systems, see Hitachi TrueCopy®User Guide (MK-92RD8019), available on the Knowledge portal.