Backing up GAD pair volumes with ShadowImage (SI) or Thin Image (TI) provides further protection for GAD data in the following ways:
- When the GAD pair is resynchronized, pair status changes to COPY. While in this status, S-VOL consistency is temporarily lost. You can protect data when in COPY status by pairing the S-VOL with SI or TI before resynchronizing the GAD pair.
- Though data in a blocked GAD pair is inconsistent, host activity can continue with the P-VOL or S-VOL. Therefore, before correcting the failure by forcibly deleting the pair, you should pair the volumes with SI or TI.
- The SI and TI pairs can then be copied, and the copies used for other purposes.