Each TrueCopy volume pair consists of the P-VOL, which contains the original data, and the S-VOL, which contains the synchronous copy of the data on the P-VOL. After creating a copy pair, you can use the TrueCopy software to split, resynchronize, and reverse resynchronize pairs, and you can delete pairs as needed to return the volumes to an unpaired status.
- When paired, the volumes are synchronized.
- When split, new data is sent to the P-VOL but not the S-VOL.
Note:
- It will continue writing to P-VOL but copying to S-VOL stops so that pair will not be synchronized.
- If setting S-VOL's write option as enable, Write access from host application of secondary site to S-VOL become possible. If not, it will hold the status at the time of pair split.
- When P-VOL and S-VOL is not synchronized, differential data will be saved as bitmap until P-VOL and S-VOL resynchronizes.
- If you resync pairs, only the data which is not synchronized will be transferred so it will save time for copying.
- When resynchronized, data that changed while the pair was split is copied to the S-VOL.
- When necessary, data in the S-VOL can be copied to the P-VOL.
During normal operations, the P-VOL remains available to the host for read and write I/O operations. The secondary system rejects write I/Os for the S-VOL. The S-VOL can only be written to when the pair is split and when the write-enable option is specified for the S-VOL. In this instance, S-VOL and P-VOL track maps keep track of differential data and are used to resynchronize the pair.